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Birth of the Power Trowel: Pumping Without Spraying – TLS #42

By Bales, Plaster, Products, Straw Bale Construction, Technical, Walls No Comments

This article appeared in TLS issue #42.  This issue includes articles about experimentation and development of bales made from various types of materials.  Articles about methods and equipment for spraying bales with plasters appear in #43 Spraying Earthen Plasters in Colorado), #33 (Stucco Pumping Iron).

by Peter Mack – Ontario, Canada

 

Mud arrives cleanly and directly through the homemade “power trowel” attached to a stucco pump.

Mud arrives cleanly and directly through the homemade “power trowel” attached to a stucco pump.

Very early on in our careers as straw-bale builders, we realized that being able to pump plaster was going to be important if we were going to attempt multiple projects. Bodies and spirits just wouldn’t be able to keep up with endless hand-plastering. So, we bought an ancient pump and started spraying.

Oh, how I remember the days of the sprayer nozzle! The comforting “farting” sound, the reassuring overspray sticking everywhere, plaster in our eyes, noses, lungs, hair, shirts and sometimes ending up on the new roof of the house we were plastering (do not trip while spraying!). The nozzle end was a tiny opening 1/2 to 5/8inch(12-16mm), so if a tiny pebble made its way through the screening and into the nozzle, it could (and did sometimes, much to our chagrin) jam up and create back pressure, even to the point of exploding the hose. Luckily no one has ever been in the way of the hose at the time, but what a sorry mess it makes!

Devising a Solution. We talked often about improving the system. I had read about trowel ends for plaster pumps before, and this kind of fitting seemed like it would be cleaner and easier to use, but it seemed impossible to find one for a large stucco pump. As often happens in life, I set about to make my own. The first step was to buy some new supplies:

  • 8-foot(2.4m) length of 1-inch(25mm) rubber air hose
  • 6-inches(152mm) of 1-inch steel pipe threaded on the outside.
  • 1-inch inline swivel (grease twice daily!)
  • 1.5-inch(38mm) cam lock coupler, NPT threads
  • 2-feet(0.6m) of 3/8-inch(9.5mm) round and square bar
  • various 1-inch hose barbs and bushing reducers
  • aluminum hawk or similar sheet metal

elev1Then I followed these steps:

  • Make a 30-degree (approximate) bend in the 1-inch pipe, leaving an 11inch(280mm) section of the pipe straight at one end. Use an acetylene or propane/ oxygen torch and wind a coupler onto the threads or they will get bent!
  • Grind a flat face roughly 3/4inch(19mm) across along the straight, 11-inch section. This is where the trowel will attach.
  • Grind a slot through the pipe in the flattened section, 3/8-inch(9.5mm) wide by 5-inches(127mm) long, centred five inches from the bend. The plaster will exit through this slot.
  • Place the flat face on the workbench with bend up and weld on four reinforcement bars flush with the face. Use the 3/8-inch square bar. These are necessary to support the trowel attachment, as the trowel material is not strong enough by itself.
  • Weld on the handle. Shape to taste from 3/8-inch round bar, remembering that heavily gloved hands will be trying to hold the handle.
  • Lay out the trowel face. An aluminum hawk makes decent material. Our trowel has very rounded corners and is 12-inches long by 6-inches wide(305x152mm), with a 3/8-inch by 4-1/2-inch(9.5x115mm) slot. Bias the slot towards the end of the trowel by 1/2 to 1-inch to allow closer application to ceilings.
  • Use a drill and saber (jig) saw to cut the trowel out. File off sharp edges.
  • The aluminum is fastened to the steel pipe with polyurethane caulking and annealed steel wires twisted tight with pliers. Our earlier experiments using Lexan for the trowel, attached by 20 machine screws failed, lasting only one or two jobs.
  • The rest is basic plumbing: use Teflon tape on all threads and heavy-duty hose clamps. As we’re reducing the hose down to 1-inch, a full size quick-connect is necessary at the upstream end of the eight-foot hose to allow for proper clean outs.
  • After trying several types of plugs in the open end of the pipe and wasting too much time searching for them at clean out time, we’ve settled into a groove using hand cut plugs made out of styrofoam. They hold just enough that, if the slot plugs up, the pressure pops out the plug. Foam rubber would probably work just as well.

elev2A New and Valuable Tool. Thus was the birth of the power trowel. It worked!  No more overspray!  We won’t kid you…we still make a mess when we plaster, but at least it’s more controlled now. The power trowel needs two operators (or one if that person is truly a power-power troweler, such as Andrew McKay!). One person handles the hose, the other holds the trowel end up against the wall. The trowel end emits a continuous “ooze” of plaster (hence the nickname “Barfing Snake”), and the speed is controlled by the throttle on the pump.

The trowel can be either moved sideways across the wall, or more popularly, up the wall. If you are using an up-and-down motion, the trowel must be held perpendicular to the ground, catching the material being squirted until you can begin applying at the wall’s base again.

There is quite a knack to this grueling job, and the pairs who are quite talented at it actually seem to dance together as they pass the power trowel back and forth, weaving gracefully around scaffolding, rocks, bales and other typical plastering obstacles.

Advantages:

  • fills hollows, good penetration into bales, flattens mud as it applies
  • less clogging because of wider opening, can pass fibre mixes
  • blow off valve works
  • less back pressure, easier on pump engine and workings
  • less loss of paste and water to atomization, resulting in longer working times
  • no more overspray on windows, ceilings and people (although we do still drop a bunch on the ground/floor)

Disadvantages:

  • overhead areas difficult
  • does not quite reach ceiling, trowelers often have to push the mud up the last three or four inches(75100mm)
  • occasional air pockets between coats
  • somewhat more physical effort for the nozzle person.

We still sometimes reminisce about the old days of the “farting” spray, and will occasionally bring it out of the closet and take it for a test drive; once a friend wanted to record it for a CD, but do we really miss it? Not a chance! The power trowel has made life as plasterers easier, cleaner and quieter.

 

Peter Mack is a full-time bale builder and a partner in Camel’s Back Construction. He is co-author of the book Straw Bale Building (New Society Publishers). Contact: Peter Mack <[email protected]> www.strawhomes.ca

Figuring the Hidden Costs in Your Building Plans – TLS #41

By Bales, Costs and Estimating, Straw Bale Construction, Uncategorized One Comment

This article appeared in TLS issue #41

by Chris Magwood and Peter Mack-Canada

This article is an excerpt from the book Straw Bale Building: How to Plan, Design and Build with Straw (New Society Publishers, 2000), and is reprinted with permission.

mistingHitting a Moving Target. There is never a single point during the planning process when you can fix an exact budget for your project. Once your plans near completion, however, you have a chance to use them as a guide for estimating both materials and labor costs.

If you find you have missed your budget target by a significant amount, you will have to go back to your plans and start making adjustments. This can be disheartening, but it is better to catch such a problem early than to run out of money before there’s a roof over your head! You may be able to adjust costs without changing your plans, if you commit yourself to finding cheaper materials and hiring less labor. If you do change your plans to reduce costs, don’t forget to work in planning that will allow you to bring your building back to its originally planned size later.

You may discover that you have apparently created plans that will allow you to build for less than what you budgeted. Congratulations! This is every homebuilder’s dream.  Don’t change your plans, however.  When the project is over, you’ll be able to spend a bit more on detailing, furnishing, and landscaping.

It Always Costs More than You Think. The building project that is completed without going over-budget is rare. Your plans will allow you to create a budget estimate, but there will always be unforeseen costs, delays, and problems that will require extra cash to solve. Leave yourself with plenty of budgetary breathing room so you can deal with the inevitable. Try to reserve at least 10 percent of your total calculated budget to cover unforeseen costs.

Pre-construction Costs. The pre-construction costs of your project will not be evident from your plans. These include the price of property, interest on your property payments, building permit fees, driveway allowances, access roads, septic permits, service and utility hook-up and municipal development fees and taxes. Depending on where you are building, these fees can total several thousand dollars and take quite a bite out of your actual construction budget. Wells, septic systems, service entrances, and the excavation/groundwork must all be completed before you actually begin construction and will take another bite out of your budget.

 

trowels

Do you have a misting pump (above), a weed-whacker (right), or enough trowels and wheelbarrows for that big plastering party? If not, better add another $500 to your budget!

Other Hidden Costs. Before you start taking count of the dollars needed for materials and labor, don’t forget to consider other hidden costs you may need to cover.  The purchase and/or rental of tools can add up to a significant budget factor.  Working without the right tools is frustrating and slow, so think your way through the construction process and make a list of what you’ll need. From shovels and picks for digging to carpentry tools and plastering trowels, the list will be extensive and expensive. Keep a bit of your budget set aside for unforeseen specialty tools you’ll need to buy or rent. For specialized tasks– plumbing, wiring, heating, roofing, concrete form work, etc.– weigh the cost of acquiring or renting the appropriate tools and equipment against the costs of hiring labor.  It may be more economical to hire labor.

Storage. Any building project can involve lots of ‘tarping up’ to cover materials from the elements. This can be especially true for straw-bale projects. Invest in enough good quality tarps to cover the walls of the building and the mounds of straw.

Power. Depending on the availability of grid power at your site, you may require a generator for your power needs. Check the costs of purchase and rental to see which is the better option.

whackerTransportation. If you are building yourself, you might find it beneficial to own a truck, van, or trailer that can be used to pick up and move materials. Such vehicles can be sold when you no longer require them, but you will need money to purchase, license, insure, and service them.

Toilets. Unless you are building in a well-serviced area, you will need some sort of on-site toilet. You can rent serviced units, or you can build an outhouse. Rental toilets are convenient and are removed when you are finished with them. They can also be expensive if the project is a long one. An outhouse requires an early outlay of time and money, but you get some building practice, and an outhouse is not a bad back-up facility to have in case of plumbing disasters in the future!

Work clothing. You will need proper clothing.  Buy good safety boots—spend extra for comfortable, well-fitting boots, gloves, and maybe a hard hat. If you are working in an inclement climate, warm and/or waterproof clothes will make a big difference to your ability to work efficiently.  Construction will wreak havoc on your clothing, so buy quality clothes or plenty of cheap, second hand stuff.

Insurance. Construction insurance covers your project in case of mishaps. Rates can vary tremendously, so get a number of quotes, and be sure you are covered for the risks that concern you most–fire, accident, damage from wind, rain, etc.

Sales tax. Don’t forget the tax man. Sales taxes can add a significant percentage to both material and labor costs. Don’t just total up pre-tax costs!

Cost of living. If you are doing your own building, don’t forget to include your cost of living while you are building. Rent and food must be covered, as will all your regular bills. If you are taking time off work to build, these expenses can take quite a bite out of your budget.

An Inexact Science. Unfortunately, budgeting is an inexact science. It is impossible to account for every contingency and glitch that may arise. The further afield you move from conventional construction, the more variables enter your budgeting equations. The only certain advice is spend plenty of time figuring out your budget, and leave lots of room for error.

Finishing Bale Walls with Siding – TLS #57

By Bales, Building Science, Design, Plaster, Straw Bale Construction, Technical, Walls, Water 2 Comments

This article appeared in TLS #57.

Loose Strings: Technical Discussions
by Jeff Ruppert – Colorado, USA
T e c h T i p s

A little known fact in the bale building realm is that a handful of people scattered across different continents have experimented with the idea of finishing their bale walls with wood or some type of manufactured siding. The technical term for siding over a bale wall assembly is a “rain screen.” The use of a rain screen (sometimes referred to a “multiple defense assembly”) on a bale wall plays the role of keeping rainwater off of the bale portion of the wall. This is in contrast to the standard way of finishing a bale wall with plaster and allowing moisture to come into contact with it on a regular basis (also referred to as “faceseal” walls). In fact, almost all of the literature to date on bale-wall construction makes the assumption that they are faceseal assemblies.

In this article, we are going to take a look at the pros and cons of in-stalling siding over a bale wall. To some people the idea of not having a plaster finish on a bale house would seem weird, mainly due to aesthetic reasons. However, for those who have chosen to use siding, aesthetics take a backseat to function due to high rates of rainfall throughout the year, as well as constant high humidity. The option of allowing bale walls to even get wet in the first place is not an option and therefore other systems must be considered.

For those of us who live in drier climates, the consideration of moisture is not as dire, therefore giving us more choices. However, doesn’t the siding option make sense if you are concerned about moisture at all? If you would like to design a building with mixed finishes, such as a combination of plaster, masonry and siding, this would open up the opportunity to include bale walls as an option on those projects. In fact, by installing a rain screen over bale walls are we not greatly reducing the potential for moisture damage, as David Eisenberg puts it, by “designing problems out of the project” from the start? We will explore these issues and hopefully offer you another choice in your search for solutions.

Rain Screens
In the old days, a rain screen was simply an exo-barrier that was attached to a building to catch rainwater and shed it before it could hit the structure behind it. The Norwegians titled this approach the “open-jointed barn technique,” since originally it was used in conjunction with the construction of barns1.

With tighter construction and newer forms of finishes, the technology of rain screens has evolved into a science. One of the advantages of using a rain screen on a bale wall is that, no matter
how you do it, it will probably add a significant layer of protection that would otherwise not exist. This assumes that you do not install the siding to accidentally direct water into the wall. The potential exists for this to happen, so just like any other type of finish, pay attention to the details!

Siding over bale walls

Siding over bale walls

No matter what type of wall you build, the driving forces of moisture will be:

  • Air pressure difference (gradient)
  • Gravity
  • Surface tension
  • Capillary action
  • Rain drop momentum.

The dominant force acting on your walls will be the difference in air pressure across the siding itself.  As the wind blusters around your house, there are pockets of less and more pressure ever changing within and around your wall assemblies. The main goal is to minimize any pressure differences so water is not accidentally driven into the wall assembly. By minimizing pressure differences, the main force acting on nearby moisture will then be gravity, drawing water down to the ground where it belongs, before it reaches your bales.

In order to equalize pressure, an air gap behind the cladding (siding) needs to be well ventilated to the atmosphere. This can be achieved through different methods, but whatever you do, make sure not to create a gap for wind to blow rain behind the cladding. This means providing ventilation behind the siding so air can pass through easily, but including a barrier at the points of ventilation to keep wind-driven rain from entering.

The advantages of using a rain screen are:

  • Adds another option for finishing bale walls (aesthetic),
  • Keeps moisture completely off the bale portion of the wall assembly,
  • Provides replaceable/changeable finish,
  • Has low or no maintenance (depending on material),
  • Uses local materials in northern climates near forested areas.

The disadvantages of using a rain screen are:

  • Plaster finish is not an option on a bale wall,
  • May not be as durable as some types of plaster,
  • Materials may not be sustainable or even available in your area,
  • Aesthetic of siding may not match your project.

Rain Screen Concept on Bale Walls

It is important to remember that no matter how we finish bale walls, they must be sealed with plaster. This means that even if we choose to use a rain screen, we must apply at least one coat of plaster. One way to install siding on bale walls is to first install nailers for the siding. These can be in the form of 2-in.x2-in. wood strips attached to the sill plate and beam at the top of your bale wall.
We recommend attaching the nailers before stacking the bales, but you can do it afterwards if you like. Once the nailers and bales are in place, one coat of plaster is applied between the nailers. A rough coat of plaster over the bales is all that is necessary. Little or no troweling is required because no one will ever see the results. After plastering, building paper is stapled to the nailers and the siding is then installed, leaving a gap behind the paper for ventilation and drainage.

One issue of concern with this method is the gaps that can occur between the plaster and nailers as the nailer wood shrinks over time. These gaps can allow air to ?ow in and out of the bale wall, creating a loss of insulating value, as well as a path for insects and/or rodents. Extra care and/or the application of caulk can take care of these gaps. Also, these gaps can be eliminated if the nailers are installed after plaster is applied. Whatever you do, be sure that a gap remains between the back of the siding and the plaster.

This is but one way to install siding on to a bale wall. There are variations to this concept, but the goals remain the same – keeping rainwater and back-splash off your bale walls. Pay attention to the details and remember the forces that are acting on water that comes into contact with your walls. Holding these basic concepts in mind will help you design your wall system. And most important, do your homework first!

Happy wall building!

Resources
1. Rainscreen Cladding: A Guide to Design Principles and Practice.Anderson, J.M. & Gill, J.R. Butterworth-Heinemann, 1988.
www.shildan.com/Rainscreen/History.htmlhttp://irc.nrc-cnrc.gc.ca/pubs/ctus/17_e.htmlwww.greenhomebuilding.com/pdf/RainScreen.pdfwww.cmhc-schl.gc.ca/en/inpr/bude/himu/coedar/loader.cfm?url=/commonspot/security/get?le.cfm&PageID=70139

Ed.Note: Jeff encourages TLS readers to send in questions and comments to The Last Straw. There may be outstanding issues that builders are dealing with that most laypeople may not aware of. There are always many questions from people new to straw-bale construction. With this in mind, this column is offered and intended to encourage everyone to educate themselves to the fullest extent regarding building construction, and we are here to help in any way we can. This forum endeavors to offer the best of our knowledge, with no claim to its completeness, but to the spirit of bale building as a continuing evolution of one form of habitat within the larger realm of natural building. We offer this forum for dialogue, with no implication of being right or wrong. This forum is for you, the learner, artisan and teacher.

Jeff Ruppert, P.E., Principal, Odisea LLC, Ecological Building, Engineering and Consulting, P.O. Box 1505, Paonia CO 81428, 970.948.5744  <[email protected]> www.odiseanet.com
Jeff has been in the construction trades for over 25 years, beginning as a laborer and draftsman on his father’s construction projects. He has spent many years working on construction projects he designs, and is a licensed engineer in Colorado.

Newsflash! Straw-bale Infill Meets U.S. Building Codes – TLS #54

By Building Science, Community, Design, Straw Bale Construction, Technical, Uncategorized No Comments

codes1This article originally appeared in Issue #54.  This issue includes a table of straw-bale building codes, guidelines and mandates in the U.S., and links to straw-bale codes, guidelines and supporting documentation; and an extensive review of the status of straw-bale codes and permitting throughout the world.

by Sigi Koko – Pennsylvania, USA

The bottom line is that yes, using straw bales for non-loadbearing infill walls meets existing building codes for both residential and commercial structures throughout the United States. Why is this true? Because building codes are not written to exclude new or alternative construction materials and methods. Rather, each building code begins with an inclusive statement such as the following from the CABO 95 Preface:

“…there are construction materials and practices other than listed in this code which are adequate for the purposes intended. These other methods represent either seldom-used systems or performance-type systems which require individual consideration by the professional architect or engineer based on either test data or engineering analysis and are therefore not included herein.”

The intent of building codes to ensure that materials are used safely and suitably, not to limit the use of appropriate materials. The burden of proof is to demonstrate that an alternative construction method meets the intent of the building code for durability, effectiveness, and safety (including fire resistance). This means showing how straw-bale infill wall systems meet the requirements of the building code for insulation value, flame spread, smoke development rating, and fire rating. Demonstrating compliance with the building codes is possible thanks to many pioneers that have dedicated time and money to sponsor third-party ASTM (American Society for Testing and Materials) tests. The results of these tests show that straw-bale wall systems not only meet the building code but, in most cases, surpass the intent of the code compared to standard stud-and-drywall construction.

Several states and counties throughout the U.S. have adopted building code amendments that specifically address straw-bale construction, though most regions do not yet include such provisions. Obtaining a building permit for straw-bale infill in regions without a specific building code is not impossible, but rather entails a non-standard process. The question is not whether you can get a building permit for infill strawbale, but rather how to best communicate with local building officials that strawbale is a viable method of construction that meets the existing building code.

David Eisenberg has written extensively and with great eloquence about how to communicate effectively with building officials, and I encourage anyone wanting more detailed information to review his writings on the topic. I have used the following strategy with success:

1) Schedule a pre-submittal meeting with the permitting official to communicate your intentions to build with strawbale. If they are not already familiar with straw-bale construction, provide printed information and additional resources. (Don’t overload with information unless it is requested; like all busy people, building officials are less likely to review a daunting pile.) Bring to the pre-submittal meeting:

• drawings of the proposed building

• an overview of straw-bale construction (I use “House of Straw: Straw Bale Construction Comes of Age” by the US Department of Energy, available at www.eere.energy.gov)

• copies of ASTM testing data (fire-related ASTM tests are at www.dcat.net)

For the final permit submittal, my experience is that stamped structural drawings greatly facilitate the speed and ease of the permitting process.

2) Remember that your building official is your ally not your adversary, and has the same goal as you: to ensure that what gets built is safely built.Acknowledge your common interest for occupant well being and safety. You will create connection instead of confrontation and open a dialog on how to achieve your common goal.

3) Be informed or hire an advocate that has experience in straw-bale construction, including how to build appropriately in your climate. The building officials will generally have more confidence in your project when they know someone on your team fully understands this non-standard construction technique. At a minimum, be prepared for the following common questions:

  • How does your wall system handle liquid water and vapor?
  • What is the fire rating and smoke development rating of the wall system?
  • Will the straw bales attract pests, such as termites and rodents?
  • What is the insulating value of strawbale?
  • How is electrical and plumbing installed?

I have to date not experienced any delays during the permitting process using this method of interaction with building officials. Increasingly, I find that building officials already possess some level of knowledge about straw-bale construction, which was not the case in this region of the country (Mid-Atlantic states) even five years ago.

Finally, I would like to address the issue of adopting existing codes and details in different climates. I design structures in a wet, humid climate with hot summers and cold winters. However, many of the now-standard straw-bale details have mostly developed in arid and temperate climates that are not necessarily durable in this mixed climate. For example, I do not recommend using rebar inside a straw-bale wall in a humid climate, since the cold metal creates an artificial dew point inside the straw wall. The result is elevated moisture around the rebar, which can lead to rotting the straw over time. Instead, I recommend external pinning or using materials that are “warm,” such as bamboo. Similarly, pea gravel at the base creates an artificial dew point, as well as creating a thermal break along the entire base of the wall. My point is not that the originally developed details are inadequate, but rather that they are specific to an arid climate. So when adopting codes and details in different regions with different climatic concerns, ensure that what you propose will perform durably in your climate.

Sigi Koko, the founding principal of Down to Earth, a design and consulting firm specializing in natural building, has obtained construction permits for many straw-bale buildings in her area. With a Masters of Architecture and several years of in-the-field construction experience, she has developed written specifications and architectural details for straw-bale and cob construction. www.buildnaturally.com

Build Your Own Simple Bale Wall Moisture Sensor – TLS #57

By Building Science, Plaster, Products, Straw Bale Construction, Technical, Walls, Water No Comments

This article appears in issue #57 of TLS.  There have been other articles about moisture sensors in recent years.

drillby Habib John Gonzalez – British Columbia, Canada

This article appeared in a slightly longer version in TLS#22/Spring 1998.

Here are the simple steps and materials needed to build your own bale wall moisture sensor:

1. Determine what depth of the bale you want to monitor and cut the 3/4-inch PVC pipe to that length.

2. Make the white pine sensor disk 1/8-in. thick to fit snugly into one end of the pipe.

3. Solder two lengths of telephone wire to two pairs of small bolts. One end of the pair of wires is bolted to a PVC pipe cap so the tips will protrude from the finished interior wall. The other end of the wires will be bolted to the sensor disk.

4. Use epoxy to glue the disk to one end of the pipe; run the wires through the pipe and fasten the other pair of bolts to the interior wall end cap. Glue the cap to the pipe.

5. Glue a perforated pipe cap over the sensor end of the pipe.

sensor6. The sensor is ready for installation in the bale wall.

7.The TimberCheck moisture meter is available from www.leevalley.com

8. A number of bale wall moisture studies were sponsored by the Canadian Mortgage and Housing Corporation (CMHC). You can get a summary of all of the CMHC moisture work on their web site www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/dblist.cfm?mode=year.  Scroll down to the bottom of the list for 00-103 (year 2000, document 103) on straw-bale moisture monitoring.

schematic

 

 

 

1. Outer end-cap
2. Perforated PVC pipe
3. Wood disk with screws
4. Wires
5. PVC pipe
6. Inner end-cap
7. Screw contacts

Siberia 2008 (Altai Project, Builders Without Borders)

By Bales, Community, Design, Plaster, Straw Bale Construction, Walls 2 Comments

This is original content and has not appeared in the printed version of The Last Straw.

In mid August of 2008 we saw ourselves back on the plane to Siberia.  This was our second trip as a group of builders and teachers to this far-away and exotic place we now consider our most remote home away from home.  Paul Koppana (Crestone, CO), Cindy Smith (Durango, CO) and myself, Jeff Ruppert (Paonia, CO) were much more comfortable this time traveling half-way around the globe having made a trip for the same reasons back in the summer of 2005.  We were to teach and transfer our knowledge and skills building a straw bale structure to a group of eager folks near the city of Barnaul.  While the goals were similar, the region and our sponsors the same (The Altai Project, Builders Without Borders) , the exact location and the participants for this year were very different.  We looked forward to meeting everyone and seeing some old faces from our previous trip.  This is the story of our time in Southern Siberia in 2008.

Bale Walls with Clay Clip

Bale Walls with Clay Slip

img_0374

Model of the Building

We departed from Denver International Airport on August 16th and flew to Atlanta where we boarded a flight straight to Moscow.  We were greeted at the airport by our Czech cohort and friend Jakub Wihan (Kuba) who speaks enough Russian to translate for us.  Kuba was present on our 2005 trip and was now playing multiple roles.  Not only was he going to be teaching his skills of wall building but he was to also translate for us when he could with his limited Russian.  In 2005 we were escorted by our leader, Alyson Ewald of the Altai Project, who organized and raised the funds for our travel.  While she was still in the capacity of the two latter roles, she was raising a newborn back home in Missouri on Red Earth Farms.  We missed her on this trip but new she was doing something much more important.

We landed in Moscow on August 17, met Kuba and made our way into the city for a long wait (12 hours) until our flight to Siberia.  The temperature was nearly 100 degrees (F) and the humidity was hovering around 90%.  We ate food, exchanged money and slept on the floor of the airport as jet lag caught up to us despite our best efforts to remain alert.  Kuba was fresh from his travel from England so he remained awake while we caught some much needed sleep.  We boarded our flight around 11p on Aug 17 and attempted to sleep during the five hour flight through three time zones to the east.  We landed around 6a on August 18 very tired and happy to see our Altai friend and hosts.

Sill Plates with Coal Slag Insulation

Sill Plates with Coal Slag Insulation

While the region and some of the folks were familiar to us, the project for this trip was different than 2005.  We were asked to help build a gallery/conference building with attached office and kitchen space for the Institute of Architecture and Design in Barnaul on their “Dacha” land which is directly south of Barnaul about 20 kilometers as the crow flies.  The building was designed by the architecture students over the past couple years as an ongoing project within their curriculum.  The result was a beautiful building using straw bale walls that stood about 14 feet tall.  The design of the building incorporated large overhangs and wrap around porches to protect the walls from the harsh winter conditions of Siberia.  To say that we were impressed with the design would be an understatement.  We thought it was magnificent, but we had doubts as to our ability to tackle all of the work needed for the walls, and then have a roof installed.  Our Siberian friends would astound us with their abilities and hard work, but more of that later.

After landing in Barnaul we spent the next few days attending and participating in a seminar for many of the Institute’s important administrators and local officials, we traveled into Barnaul for an art exhibit by one of the students who was also one of our translators, and we visited family of one of the professors and ate dinner.  We spent these days talking with Lena and Sergei, our main hosts and the Deans of the Institute directing the project, about building details and what materials we would need.  There were already bales on the site and the foundation was freshly poured.  There was no wood for the frame, nor any mesh or clay for plaster.  Cindy and Kuba immediately began looking for a source of clay which would prove to be a long and difficult task.

Our first step was to have the carpenters install the sill plates.  These turned out to be 6×6 timbers that were nailed into the foundation with blocking every several feet.  The spaces between the sills were filled with coal slag, which it seems is commonly used as an insulating material in Siberia.  On Aug 21 we built the first post as an example for the carpenters, which they copied many times to creating all of the window and door bucks, as well as corner framing.  The top plate was to be flat 2x material layered with joints staggered at post locations.

Bale Stacking

Bale Stacking

By the 23rd of August the posts were installed and braced around the main gathering space.  We were pressed by our hosts to teach a “workshop” and educate everyone in bale-stacking.  Paul and I described how stacking bales worked and showed them how to re-tie a bale.  The bales were of marginal quality so treating them delicately was very important.  The eager participants soon took over and were stacking away.  Within an hour three walls were substantially complete and we made everyone stop due to the questionable weather approaching.  We needed to cover our work before it was soaked by rain.  The carpenters also needed to construct the top-plate assembly so the top bales could be installed.

All of the bales on the main room were installed by the 25th and we began using plastic lath, or mesh, to reinforce the joints between straw and wood.  Without a stapler, we attached the mesh to the wood with nails bent over and we had some of the students make pins out of wire for attaching the lath to the bales.  Much of this work was loose by the time we began plastering, but it was still good to have it held in-place with something.  By this time, no clay had been found despite a few forays by Kuba and Cindy into the neighboring countryside.  It seems that any people with a pit of clay did not want to share it.  We were in an ancient floodplain where the river had deposited silt and sand, but left little clay exposed that was available for use. It seemed very frustrating as loads of “clay” would show up that was not suitable as a plaster material.  Cindy was becoming frustrated and unable to find a solution.

By the 27th clay arrived as Cindy and Kuba had found a source.  It was good quality so Cindy had the volunteers begin applying a clay slip to the walls while others prepared cob to stuff into voids.  The work was fun and we could finally see the project happening.  Our hosts, however, had bigger plans.  We were asked our opinions about how far we could go during our three week visit.  We were scheduled to leave on the 31st which was less than a week away.  We strongly encourage our hosts to focus on the main structure and get a roof installed before attempting any more new walls.  They charmingly went ahead with their plan of having the lower walls framed, bales stacked and the shed roof framed.  At this point a group of twenty or so students showed up to work for a few days.  The results were nothing short of miraculous.  Where we thought they were flirting with disaster, they used all of the skills we taught them and managed to not only frame and stack the lower walls, but plaster them with two coats of plaster before we left.  We were amazed!

Having witnessed how slow things can go in Russia, we could not believe the motivation that was instilled by our hosts in their students and other volunteers.  Not only were they dealing with the workshop, but they had a budget that was running out and needed to be refunded by the Institute.  If they failed to meet certain deadlines the building would not be finished.  We watched Lena and Sergei expertly navigate a sea of regulators, engineers, administrators and volunteers, all the while smiling as we appraoched never missing an opportunity to treat us like family.  The experience was humbling to say the least.

Students and Volunteers

Students and Volunteers

As the clay slip was applied to the building, we asked about electrical wiring.  No electrician had been hired and we were getting ready to seal the walls.  I created an electrical plan with Lena and some students, some wire was produced along with boxes.  The boxes were nailed to posts and lathed in-place.  Wiring was run up the posts through the top plate where all wiring would be figured out later.  We decided on the location of the electrical panel so I could plan where runs would be made later.  It was another last-minute detail, but we were able to do what we needed before it was too late.

Most of the plaster was mixed by hand due to a malfunctioning mixer.  We limped the mixer along until it was completely dead and then had the students team up in groups to make plaster.  They were able to keep up well with the dozens of people applying it.  By the time we left, a slip coat and one coat of plaster had been applied to the entire building.  Plastic tarps were used to protect the tops of the walls and drape over the rafters of the lower roof.  We held our breaths praying for dry weather.  We had seen rain on and off most of our visit, but not in large quantities.  All we could do was hope for the good fortunes of our amazing friends to continue.

We received pictures of the final building just before Christmas.  The building has been completed!  They have lime-washed the earthen plaster and installed siding where needed.  The roof is on and the interior is finished.  There are two truth windows that are the largest we have ever seen.  They didn’t seem to be swayed by opinions such as “the plaster is a rigid part of this structure.  Leaving it off large expanses of wall may not be desirable,” or “If bugs and rodents do get inside your walls, it will be like a movie theater for visitors.”  The desire of these folks to push their limits gave us pause at times and we are impressed by their resolve in the face of possible disaster.

Clay Delivery

Clay Delivery

Lessons were learned about working with the locals even if it meant doing something in the wrong order or what seemed to be the wrong way to us.  They have their ways of doing things and even though we thought we could help them, there was great resistance to our ideas at times.  Stepping back and letting the owners of the project remain in control no matter what was happening seemed to give them a sense of determination that would not be derailed.  It turns out that they did not ignore or resist our ideas as we had thought.  They listened and integrated them into their program in the best way they could.  What became clear to me was that we were working with formally trained architects and students of the classical ways of architecture.  They paid attention to details and form.  On this project the function drove their form more than what seemed typical.

Finished Building

Finished Building

This building took all of the lessons they were taught about bale buildings and integrated them in a very functional way.  They used large overhangs.  There was not a single bale wall over 2 feet in height that was not protected by a wrap-around porch.  They used earthen plasters even in their extreme climate where temperatures reach -50 degrees (F).  They finished the plasters with a lime wash that will be easily maintained over time.  They installed two huge masonry fireplaces as thermal mass.  There is almost no solar gain due to the dense forest so they reduced glazing on all walls to what was necessary and functional.

Truth Window

Truth Window

We left Krona on August 30 after a quick award ceremony where everyone received some thank you certificate and a book on the design of straw bale houses – a first of it’s kind in Russia.  Our next stop was the old building that we helped build back in 2005.  That project was 6 hours south by car so we kicked back as best we could in the smallest car we could imagine and rested until we arrived in the heart of the Altai Republic and back in Chemal at The Milky Way.  We were interviewed by a video production group and welcomed generously by our previous hosts.  They had erected a handful of wood-framed cabins for guests and used the bale building as a tourist attraction and gathering space.  The plaster is holding up much better than we thought.  It is also earthen with a lime wash.

The 2005 Project near Chemal

The 2005 Project near Chemal

On Sept 3 we were in Barnaul and boarding a plane back to Moscow and then onto Colorado.  It was another magical trip and one that was more successful than any of us thought possible.  The memories of bania (sauna) with friends every other night, meeting the families of our Siberian friends, working alongside our gracious hosts Lena and Sergei, and dancing around the campfire with all the volunteers who showed up for two weeks to help us and learn how to build with bales made for a deeply rich experience.  We look forward to seeing everyone again some day and to visit those two important projects that brought straw bale construction to the Altai region of Siberia.

We would like to thank the following organizations for their contributions and hard work:

The Altai Project
http://altaiproject.org

Trust for Mutual Understanding
http://www.tmuny.org

Builders Without Borders
http://builderswithoutborders.org

Institute of Architecture and Design in Barnaul

Fund for 21st Century Altai

Bale Preparation – TLS #50

By Bales, Plaster, Straw Bale Construction, Walls No Comments

This article originally appeared in TLS issue #50, 2005

Load-bearing walls waiting preparation

Load-bearing walls waiting preparation

by Tony Caniglia – Colorado, USA

This technique was developed to reduce the amount of fill with loose straw or straw/clay required when the bent (rounded) sides of the bales are butted together. The purpose is to remove the bulge on the ends of the bales so that the bales are squared up and fit right up tight together.

Prepping the bales before stacking them can help make them nice and square.  Do this somewhere away from the house or building for fire safety, to keep the dust away from other workers, and to collect the loose straw that will be created.  Start with a large number of bales. Use a couple of other bales to help hold one bale stand up on end. With your chainsaw, cut downward a few inches next to the strings on the end of the bale and move the chainsaw out toward the edge of the bale.  The bales may have a little roundness between the strings, so clean that area up, too. Try and keep your chain saw level, and don¹t hit those strings! Step back to eyeball it to see if the bale looks square. Clean up 6 to 10 bales, then set the chainsaw down and flip all the bales over to stand them up on the other end, and do the other side. You may have to lay the bales on edge and, with a little jump, put your knee into the bale or hit it with a sledge hammer if it has a curve to it. You could also lay the bales flat on top of a bench, if you don¹t want to bend over or want to keep the bale stable (another person working with you can help make this work easier, too).

You may occasionally hit a string with your chainsaw, say one out of ten, but it is easy to restring the bale. Just tie another piece of string  about 16 inches long to the cut string and make a loop knot on one end. Put the other end through the loop, crank it down (pull it tight) and tie it off.  Once square, the bales push together better and will help make the walls more stout with less voids. This means little or no stuffing with loose straw. When the bales are stacked, grab a 4-ft level, a couple of sledge hammers (or other ³bale bangers² as you prefer) and get another person to help. One of you should stand on the inside of the wall and the other one on the outside of the wall. Smack the bales so they don¹t overlap one another too much. Focus on getting one side as plumb as you can (for example, work on getting the inside plumb). Now trim the surface of the bales on both sides of the wall (inside and out) with a chainsaw or weed whacker. Be sure to do the whole wall, top to bottom. That will help to finish cleaning up any overlapping bales and any humps, bumps and lumps. This nice, plumb wall will make your lathing, netting, plastering and troweling process easier, not to mention the money you will save in stucco materials! And these beautiful, straight walls may make your building easier to sell in the future!

Tips about Bales – TLS #50

By Bales, Straw Bale Construction No Comments

This article originally appeared in issue #50, 2005

by Joyce Coppinger – Nebraska, USA

p8060026Tips about Bales
Why wait until you have the framing done and the roof on before finding your bales. Find your bales during the planning process and well before you begin construction. Knowing the size of the bales before you design the building will help you determine wall spans and wall heights, perhaps saving some of the cutting and retying of the bales, and can help you decide how to stack the bales­ flat or on edge. Placement of windows and doors may be easier to determine. You will even have time to select the best bales to use, eliminating those that might have weeds and seeds, signs of moisture or mildew, or aren’t shaped or tied well. For help in finding and buying your bales, try these web sites:

www.strawlocator.com – At this web site, you can list the specifications for the bales you need for your project, and you can search the listings of bale suppliers.

www.hayexchange.com – Remember “hay” is not “straw” when searching this web site.

The article titled Bale Wisdom-Bale Buying 101 lists 20 tips for buying your bales, information on bale orientation, bale storage and handling bales.

When you know the size of the bales in the design process, you can calculate wall heights so that you have full bales in each course, eliminating the need to fill flakes and cakes at the top of the wall. You can also calculate the placement of windows and doors so they fit readily into the bale courses as they are stacked and/or the framing for the windows can be spaced so a full bale fits under and above the windows and above the doors.

Trimming the bales to eliminate the bent or folded (rounded) ends will give you a rectangular unit to work with. All sides of the bale will have cut stems and, when the bales are stacked, will lock together better­top, bottom and sides. The triangular hole between bales that occurs when bales are not cut will be eliminated, so you won’t have to stuff as much loose straw or light straw/clay fill between the bales and bale courses. (See Tech Tip, pg 23)

Sustainable Living in California – TLS #59

By Bales, Design, Walls No Comments

This article appeared in TLS #59.

semmes1Turko Semmes is a licensed general contractor from San Luis Obispo County, California, and one of the foremost experts in straw-bale building techniques.

semmes2A graduate from the Architecture Department of Cal Poly State University in 1978 with a degree in Construction Engineering, he has been self-employed since that time, running a custom home building business specializing in energy efficiency and sustainable building techniques. Turko is a co-founder of the California Straw Building Association. He has built several custom homes, agricultural buildings, and wineries throughout central California. He has taught classes and workshops on sustainable building systems to community groups and to students at the elementary, secondary, and university level. He is recognized as an expert on passive solar design concepts and other energy efficient techniques, as well as nontoxic and sustainable building materials.

semmes4The Semmes southwest-style straw-bale home (pictured here) is nestled in the Los Padres National Forest in a setting that joins nature with natural building. The courtyard/pool area is an inviting setting filled with flowers and hand-painted artwork at the main entry door leading to Turko’s office and the family den. The lower terrace provides space for relaxing poolside with an outdoor shower nearby. The upper terrace is a covered outdoor cooking and dining area. The formal living and dining rooms and the master bedroom face onto the meadow with views toward the mountains of the Santa Lucia Range. The cool and calming color palette of the master bedroom contrasts with the bright and lively colors of the other living spaces.

semmes5Turko Semmes, Semmes & Co. Builders, Inc., Atascadero CA
<[email protected]> www.semmesco.com
semmes3Photo credits: Semmes & Co. Builders, Inc.

 

 

 

Better Quality, Ecological Correctness through Sustainable Design – TLS #59

By Bales, Community, Design, Fire, Uncategorized, Water No Comments

This article appeared in TLS #59.

by Ken Haggard and Polly Cooper – California, USA

Adopted from an article that appeared in Home Power Magazine.

Straw-bale cottage during construction.

Straw-bale cottage during construction.

Like many other architectural firms in California, San Luis Obispo Sustainability Group architects had been designing building that utilized passive solar for many years. Like many other architectural firms around the country, and around the world, in recent years we found ourselves shifting our design work to “sustainability,” an extension of passive solar design concepts.

The definition of sustainability we use in our work is to use resources that meet our needs but do not compromise the ability of future generations to meet their needs. As our firm and the work we do evolved, our practice has evolved to encompass broader issues including life cycle impacts of materials, miniaturization of infrastructure, health issues in buildings, permaculture and landscape regeneration.

By 1994, we had developed a comfortable working environment, consisting of a mix-used passive solar complex that included an office, shops and a residence on an old trout farm adjacent to the Los Padres National Forest, 12 minutes north of the city of San Luis Obispo. Little did we imagine that we would endure the trauma of losing nearly everything we owned or that this tragedy would afford an opportunity to redevelop our complex based on our new knowledge of sustainability. In August 1994, the 41 Wild Fire that burned 40,000 acres/16,200 hectares in our area destroyed our entire complex, and forced us into applying these broader principles of sustainable design for ourselves. Once we got over the initial shock of losing an extensive library, slide collection, office and home, it became more and more obvious what an opportunity our natural fire-oriented local ecology offered us – we could start from scratch and build sustainably, without the problem associated with retrofitting existing structures.

One of the first things we realized was that the fire had left us with a large inventory of building material. (We had several strawbale benches on the site before the fire. They turned out to be more fire resistant than most of the stucco-, tile- and metal-clad buildings in the canyon.) It had killed most of the mature trees (except for 2/4 of the fire-adapted oaks), and these trees were now available to use as lumber. We would never have dared touch them while they were alive. In addition, the massive opening-up of the landscape afforded by the fire allowed us to examine our aging infrastructure. We realized it could be redone in a much more sustainable way. Landscape regeneration became an everyday reality, not some theoretical subject. We suddenly could do things that we had only talked about, but never had the time to do – like getting off the electrical grid.

cottage2

Completed straw-bale cottage.

Right after the fire, it was necessary to develop a base of operations – a place to store tools, plan from and live in. We attempted to combine this need with several others, such as providing future retreat for guests and visitors, as well as a demonstration workshop for our senior sustainable design architecture class at Cal Poly State University. The result was a 500 sf/46m2 cottage that we built on a slab that was left from a shed we had removed long ago. his was one of the few slabs in the canyon not destroyed by the re, because it supported no flammable building at the time. For the structure of this building, we used fire-damaged telephone polls with a truss joist frame. We built the walls from rice straw bales laid on edge, which provide good insulation. In addition, the stucco finish provides interior distributed thermal mass. For the ceiling, we used wheat straw bales laid flat between TJI rafters, which also provide good insulation. The roof is corrugated steel sheet, and includes a 4-ft.x 8-ft/1.2mx3.4m skylight with skylid (movable insulation) unit. Our electrical power came from a Pelton wheel (a microhydro system) on the creek connected to storage batteries.

The construction of this building used healthier building materials that produced less waste. The unused straw was used for erosion control on the site. The building also gets much of its heat from the sun, and uses waste as a resource. In addition, the structure served as a prototype to test details that we planned to use in the larger buildings.

Sustainable Materials

In sustainable design circles, there is a lot of talk about the advantages of using regional materials. As practitioners, we always had nagging doubts about how much of this is truth and how much is idealized theory. Once construction of the guest cottage was underway, we turned our attention to testing this theory. There were several stands of mature trees on the site, especially in the creek areas. The oaks, Sargent cypress and several pine species were native. The Douglas fir and redwoods were not, although their natural range on the coast extends to just 10 miles/48 km north of the site. They were planted 33 years ago when the trout pods were developed. After the fire, all the redwoods put our new growth immediately, and three-quarters of the oaks sprouted from at least part of the remaining trunks. The other trees were killed. We now had an opportunity to do what passive solar applications do – use resources directly on the site rather than importing them from far away and exporting the impact elsewhere.

We felt obligated to mill the dead trees into lumber for reconstruction. We hired sawyers to do this during the fall of 1994, suing a wood Miser portable mill. Both we and the sawyers were amazed at the quantity and quality of wood produced in this relatively small area. We harvested 22,000 board feet of lumber, enough for construction of the other buildings with enough left over to be a storage, rain and sun protection chore. The economics of this also created the unusual condition of using straw-bale construction in conjunction with heavy timber construction, as it was more economical to mill big pieces rather than small ones.

The result of this experience was very interesting. The wood we obtained cost about the same as it would have from a lumberyard, but the quality was much higher. In addition, all phases of the life cycle of this material – source, transport, processing, use and source regeneration – happened on the site. Waste could not be exported elsewhere. It became a resource used for erosion control and organic matter for the regenerative process.

It became obvious to us that although the first costs of both milling our own lumber and buying it from a lumber yard were about the same, the long-range environmental costs of milling our own was much less. These costs are not often accounted for in our present economic system.

The Studio/Office

interiorThe next step was construction of the studio and office, completed at the end of March 1995. Because of the function of this building, we placed great emphasis on natural lighting in addition to the passive solar design. The studio/office is also off-grid, powered by photovoltaic (PV) panels over the library/research area, with a Pelton wheel on the adjacent creek for use as backup in the winter when the water is high. (Two streams fed by the nearby mountain range flow through the property.) The studio/office is heavy timber-frame construction with straw-bale infill.

The south side of the office is configured to allow maximum sun penetration in the winter and begins to shade itself in early April. During the summer months, it is totally in shade, picking up sun again in late September. Parts of this facade are view windows, part unvented 12-in./30cm Trombe walls that also act as shear walls, and part 9-inch-thick/23cm water tanks below the south-facing window on each end that act as indirect gain passive heaters. The Trombe walls and water tanks are painted with a selective surface paint on the sun-facing side.

The wiggly light shelf on this south facade serves two purposes: providing summer shading of the windows and low water tanks and throwing light deeper into the building in winter. This office is also designed for maximum night ventilation. Summer breezes generally flow from southwest to northeast, so the air moves through the long dimension of the office. These breezes, coupled with the large amount of distributed thermal mass in the building, keeps the interior temperatures below 79oF/26oC, even when daytime summer temperatures are quite hot, occasionally reaching 110oF/43oC.

The Residence

The two-story residence of the complex was completed in October 1997. We used construction techniques similar to those in the office, except that the heavy timber structure is placed 6 in./15cm inside the straw-bale walls. This configuration allowed us to expose the beautiful timber frame and create a continuous two-story straw-bale wall without interruption of the north side. The curves of this wall were very easy to achieve with straw bales without any added expense. This is the best arrangement of the timber structure and bale walls we’ve found to date. There are remarkably few cracks in this wall. The contrast to the stuccoed wood shear walls on the east side is very telling.

The residence uses interior 8-in./20cm concrete block walls as shear walls, thermal mass and decorate “gates.” Besides south-facing glass, skylights provide direct gain, with skylids as thermal control. We’ve found that this system offers more flexibility in the fall and spring than fixed overhangs.  The El Nino weather pattern sometimes produces a very unusual cool late spring, which we cannot respond to in the studio with its fixed overhangs. The skylight/skylid arrangement in the residence did allow us to respond to these unusual climatic conditions. The residence is also off-grid, powered by the PV system and Pelton wheel backup that provides electricity to the rest of the complex.

Landscape Regeneration

exteriorOne of the unexpected joys of this whole ordeal has been to experience the rapid regeneration of the landscape following the fire. Fire is such an integral part of the native California landscape that everything is set up for it. The first spring was dominated by delicate fire poppies, which only appear in newly burned areas.   In this case the seeds had been waiting 60 years for their chance – it had been that long since this area last burned. The next year was dominated by morning glories, which spread all over the armature of the burned branches of earlier plants. The third year was the year of low herbal plants – sages, bush poppies, soap roots and others.  In the fourth year, we found the Ceonothus (wild lilac) dominating. The regeneration of oak and cypress trees then began to be much more noticeable.

The best wood for reconstruction turned out to be the Sargent cypress, used for the structure and trim. Alder was the best for cabinets. The cypress trees regenerated naturally because they were a fire species whose seeds are stimulated when they are burned. When the office was done, to commemorate the wonderful alder cabinet it contains, we planted several times the number of alders in the creek than were there before the fire.

Better Quality, Ecological Correctness

We’ve found that the application of our design theories to our own situation has helped convince clients and others that sustainability is more than just another theory. It is a way of achieving better value while simultaneously having far less impact on our planet. In fact, once we get beyond the fears of scarcity that haunt our industrial culture, we will see that these two values – better quality and ecological correctness – are interrelated.

Ken Haggard and Polly Cooper are principals with the San Luis Obispo Sustainability Group, 16550 Oracle Oak, Santa Margarita, California 93453; 805.438.4452, fax 805.428.4680 <[email protected]> www.slosustainability.com

Ed.Note – An article about the curved wall straw-bale workshop building (not pictured in this issue) at Ken and Polly’s complex will be included in TLS#60/Details, Details, Details. It’s amazing in its design and structure.

Building Bale Sources

By Bales No Comments
Straw Delivey

Straw Delivery

How to Buy a Bale
The article “Bale Wisdom/Bale Buying 101” explains the things you need to know about buying bales for your building.

How to Find a Bale
Listings of bale sources are no longer included in the TLS annual resource guide. For the most current listings of bale sources, visit www.strawlocator.com, www.hayexchange.com and www.agriseek.com/sale/e/Ag-Products/Plant/Cereal/Straw-Bale.

These sites list suppliers and sources. You can also list information about the bales you need on the www.strawlocator.com site and identify bale haulers and shop for supplies.

“Like a lot of things, older balers are often better balers.  Newer rotary combines, for example, do such an effective job of getting the grain off the stalk that there’s hardly any stalk left to bale. Yes, the bales from a rotary combine seem good and tight… but look closer.  Try grabbing at a corner of a bale.  Can you pull straw off the bale easily?  What length is the straw?  Is it all 3-4 inches (7-10 cm)?  Try to avoid buying these bales.  Longer straw makes a far superior structural bale, and it’s easier to work with, too.  If you do end up with bales from a rotary combine, and you have to work with them, avoid any unnecessary handling and notching.  Their instability will be readily apparent as soon as you start making custom bales—it could even be a structural issue if you are building a load-bearing structure.

This may only apply to two-string bales—so far we have not seen a three-string bale with this problem.  Whatever the size, do check out the bales you plan to buy, before you write the check.  All bales are not created equal.”

—Chris Magwood, TLS guest editor

Other good sources to track down people who can do custom baling are the local co-op, feed store, parts store, or any ag-related business. Also contact your local sustainable agriculture society, food cooperatives, and cooperative extension agents.
There are board, commissions and associations through which you may be able to find custom balers for all types of bale-able materials – wheat, rice, hemp and others. This is a great way to create awareness on the part of growers and balers, and a way you, too, can help spread the word about bale building. Here’s a few we’ve been in touch with to promote the use of straw bales for construction:

UNITED STATES
California Rice Commission
701 University Ave., Ste 205, Sacramento CA 95825

California Wheat Commission
PO Box 2267, Woodland CA 95776-2267; 520.661.1292, fax 530.661.1332.

Idaho Grain Producers Association
821 W State St., Boise ID 83702-5832; 202.345.0706.

Idaho Wheat Commission
1109 Main St., Ste 310, Boise ID 837-2-5632; 208.334.2353.

Illinois Wheat Growers Association
RR4 Box 145, Greenville IL 62246.

Kansas Association of Wheat Growers
315 Houston St., Suite C, Manhattan KS 66502.

Kansas Wheat Commission

2630 Claflin Rd, Manhattan, KS 66502-2743,; 866.75WHEAT.

Minnesota Association of Wheat Growers
2600 Wheat Dr., Red Lake Falls MN 56750; 218.253.4311.

Montana Grain Growers Association
PO Box 1165, Great Falls MT 59402; 406.761.4596.

Montana Wheat & Barley Committee
PO Box 3024, Great Falls MT 59403-3024; 406.671.7732.

National Association of Wheat Growers
415 Secont St., NE, Ste 200, Washington DC 2002-4993; 202.547.7800.

North Dakota Wheat Commission
4023, State St., Bismarck ND 58502-9690; 701.328.5111.

Oklahoma Wheat Commission
800 NE 63rd, Oklahoma City OK 73105; 405.521.2796.

Oregon Wheat Growers League
115 SE 8th St., Pendleton OR 97801; 541.276.73390.

US Wheat Associates
1620 I St. NW, Ste 801, Washington DC 2006-4005.

US Wheat Associates
1200 NW Naito Pkwy, Ste 600, Portland OR 97209; 503.223.8123.

Washington Association of Wheat Growers
109 East First, Ritzville WA 99169; 800.598.6890.

CANADA
Canadian Wheat Board
423 Main St., PO Box 816, Station Main, Winnipeg, Manitoba, Canada R3C 2P5; 204.983.3101, fax 204.983.4678.

There is also an interactive listing on the web page for the California rice straw market. Go to ricestrawmarket.org.

Bale Wisdom – Bale Buying 101

By Bales, Straw Bale Construction, Technical No Comments

This article was originally printed in the 2003 Resource Guide

Compiled and updated by Joyce Coppinger from the writings of Judy Knox, Kim Thompson, books on strawbale, and US Department of Energy.

communityIn most cases, it is advisable to find a source for your bales early on in your project planning as the size of the bales may influence how you lay the bales in the walls or bale orientation, wall spans, ceiling heights and other design considerations. And, be sure that the bales are stored under cover, preferably in a barn or storage building, until they are taken to your construction site.

Twenty Tips on Bale Buying
1. Purchase bales following the harvest when bales are usually inexpensive and abundant. You may need to contact local farmers during planting season about growing and custom baling.
2. Make sure the bales are stored high and dry from the time they come out of the field until they are installed in your building’s walls.
3. Don’t rely on hearsay about the size and condition of any bales you might buy. Check out the bales yourself.
4. Bales should be “bright” and dry with no sign of moisture, mildew or mold.
5. Test some portion of the bales you select to make sure they have always been dry.
6. Bale moisture content should be 14 percent or less. (Use a digital probe or moisture meter.)
7. An ideal proportion of a bale in size is twice as long as it is wide. This simplifies maintaining a running bond in courses.
8. Commonly available bale sizes: two-string, 14 inches(36cm) high x 18 inches(46cm) wide x 35-40 inches(91-96cm) long, weighing about 50 pounds(40 kg); three-string, 16-17 inches high x 23-24 inches wide by 42-47 inches long, weighing about 75 pounds(60 kg).
9. Try to get bales of equal size and length. If they do vary in length, as many will, lay ten bales end-to-end. Measure this entire length and then divide by ten. This is the average bale length to use for planning and designing purposes.
10. Bales should be free of weeds and mostly free of seed heads.
11. Wheat, oats, rye, barley, rice or flax are all good bale materials. Some grasses can be used for bales (switchgrass, for example). Do not use alfalfa or other brittle stemmed plants. Other materials are now being baled, such as paper and cardboard (See TLS #42/New Systems).
12. Look for thick, long-stemmed straw. Straw of 3-4 inches or 7.5 to 10.2 cm is not recommended. The stem length will vary depending on the type of baling machine used.
13. The R-value and other properties of your bale (tensile strength, moisture content, burnability, for example) will vary depending on the type of plant or crop residue used.
14. Dealing directly with farmers may give you more say about bale quality and consistency.
15. Expect to pay extra for transportation and storage.
16. Wholesale brokers offer direct access to the bale supplier and often offer commercial transportation.
17. Retail outlets and feed stores are the easiest source to access, you will probably pay more for your bales than those you buy from a broker or directly from the farmer.
18. Bales must be tightly tied with durable material, preferably 240-lb. knot strength polypropylene (usually won’t decompose) or hemp twine or 16-gauge galvanized baling wire (usually won’t rust). Avoid bales tied with traditional natural fiber baling twine (sisal, for example).
19. When you lift the bale, it should not twist or sag. The flakes (sections within some bales) should not pull apart easily.
20. Make sure the bales are uniform in size (as much as possible – there will be some variance) and are well compacted.

Bale Orientation:
Bales can be laid flat (strings between courses, the wider side laid parallel to the ground). When the narrower of the two sides is laid parallel to the ground, the bale is being laid “on edge.” Bales can also be placed on end in small spaces where vertical stacking is required. The recommended placement for two-string bales is flat. Three-string bales can be used either flat or on edge. The R-value for two-string bales is believed to be approximately the same regardless of placement.
Flat placement provides maximum wall thickness and is more stable during construction. It also offers greater resistance to vertical compression. If a wire or string fails, expansive forces will be parallel to the wall and will be contained by the surrounding bales. Notches up to 5 inches can be cut into bales without severing a string or wire. Beveled bales can be more easily created for filling in the eaves of a peaked roof.
Placing bales on edge creates more wall height and bales can be cut parallel to the strings for placing windows. It also makes attaching stucco netting easier, because it can be fixed directly to the strings.

Bale Storage:
Storage should be off the ground, preferably in a barn or storage building. If outdoors, preferably on pallets, to keep ground moisture from being absorbed, and covered with high quality tarps to keep the bales dry. The tarps should cover each side of the stack of bales by at least one bale. The stack should be crowned (built to a peak at the top) to keep water from standing on the tarps and perhaps leaking into the middle of the stack through cuts or holes in the tarps. Best if the top row of bales (around the perimeter of the stack of bales) has a slight overhang to help protect the sides of the stack.
Inexpensive tarps and rolls of plastic are not preferred as they may tear or puncture easily, making moisture penetration into the bale stack more likely. Covering the bale stack with plastic sheeting and then covering the sheeting with tarps could help keep moisture away from the bales. Anchoring the bales securely is not always easy, but it’s very important, especially to protect the bale stack from strong winds and storms. Weighting the bale stack down with old tires, cement blocks, or logs tied to the end of a rope and attached to grommets in the tarps’ edges is a good method for anchoring the sheeting and tarps.

Handling Bales:
Most bales are easy to move around and stack. However, two people lifting and moving the bales will speed up the work and reduce body strains. Baled material can be scratchy and itchy as well as dusty – so long-sleeved shirts and pants, dust masks and gloves should be worn. Hay hooks can be helpful.
Lifting and throwing bales can be eased by using your body weight and the momentum of a swing or toss. Probably best not to try to just muscle them around when moving and lifting the bales. Use a wheelbarrow or large wheeled dolly to help with bale moving and, in some instances, heavy farm or construction equipment such as a small crane, a tractor with lift, could be helpful.
Bales can be used for stairs and as scaffolding – but caution is the word, as baled material can be slippery. And, keep loose straw raked and stacked away from the bale walls and the construction area, as it is highly flammable and dangerous underfoot.

Straw-bale Sound Isolation and Acoustics – TLS #53

By Building Science, Design, Sound, Straw Bale Construction, Technical, Walls One Comment

This article appeared in TLS #53.  The topic of this issue is Moisture.  It contains an extensive article about Moisture Basics and Straw-Bale Moisture Basics (by John Straube, edited by Bruce King)  it also includes articles on moisture meter accuracy, moisture sensors, seismic resistance, and plaster testing.

by Rene Dalmeijer – The Netherlands

In June 2003, Jasper van der Linden, a building engineering student at the Eindhoven Technical University, Eindhoven, The Netherlands, tested the sound isolation of an earth-plastered straw-bale wall. Rob Kaptein of RAMStrobouw and I assisted in carrying out the test. The test was executed in a true acoustic test chamber according to ISO 140-3. We were able to execute a consistent test giving a good indication of how well a plastered straw-bale wall retards sound.

Based on the outcome of the test, it is to be expected that a reasonably well-designed and built straw-bale wall without acoustic defects (like protruding post-and-beam members) will perform in the region of 53dB and upwards (55dB with A weighting; “A-weighting” means the impedance is corrected to approximate human hearing sensitivity, which varies depending on frequency). The 2dBA increase in performance when compared to the test is mainly because we used very thin (worst case) plaster thickness in the test sample. Normally earth plaster finishes would be thicker. This puts the performance of a straw-bale wall at more or less the same level as a decoupled brick cavity wall and even exceeding it in the critical low-frequency region.

Most everyone who has been in a straw-bale building has had the sensation that interior sounds somehow seem louder, because interior sounds become more distinct for not being drowned out by background noise coming from the outside. This is a clear indication that straw-bale walls work very well as an acoustic insulator. Normally built structures depend on high mass for good sound insulation. But there is also another way of achieving good sound insulation, which depends on a damped cavity surrounded by two not-sostiff membranes with sufficient mass. A straw-bale wall, specifically with earth/clay plasters, is an excellent example of this alternative way of achieving good sound insulation, as the test result clearly illustrates.

The Test

The test was executed in the acoustic lab of the Eindhoven Technical University. The test and test facility is according to ISO 140-3 which is to test the sound isolation of building aperture of two acoustically separated chambers (the test sample is placed in an aperture between the chambers). Although I am aware of the limitations of the test facility for testing a wall system, we have endeavored to make this test as accurate and as representative as possible. The aperture’s size (ISO 140-3 std) is 1.88m2 /20 ft2. The tested straw-bale wall section had the following configuration:

  • Two-string (460mm wide building quality bales laid flat density 120-130kg/m3)
  • Earth/clay straw plaster 25mm and 35mm (intentionally asymmetrical cover)
  • No reinforcing plaster netting or mesh or any form of pinning

table1The chosen sample structure was to be as representative as possible of a normal earth/clay plastered straw-bale wall structure as used by the experienced straw-bale builder Rob Kaptein of RAMstrobouw. Rob was also responsible for manufacturing the test sample. The graph and table summarize the test result.

[Rene’s comment on the measured performance: The result can be expressed as 53dB according to A-weighting. Actually expressing the sound isolation value in one number (i.e., 53BA) is a simplification. In actual fact, giving the performance at each of the various frequencies is much more meaningful.]

Generally this is done at either one octave intervals (1/1oct) or at one-third octave intervals (1/3 oct), the last giving even more detailed information.The graph and table show both measurements (not A-weighted). The dip at around 250Hz is due to the transition between the masws and damped cavity odes of operation of the test sample and should be largely disregarded as part of the vagaries of a test.

The 53dBA test result might seem low but in fact is very good. Most conventional wall systems including a brick cavity wall with much higher mass have a lower performance. Specifically interesting to note is the 2-3dB better performance at very low frequencies of the straw-bale test sample when compared to brick-wall systems. Nearly all wall systems, including stick frame, are able to sufficiently subdue high-and mid-frequency sound, but low-frequency sound is problematic. In practice, better performance at low frequencies is worthwhile because it means that the ever-present background noise in suburban areas is perceptibly reduced.

Recipe for Straw-bale Wall Acoustic Isulation

Besides sheer mass, low stiffness with sufficient mass and acoustic decoupling are very imortant for acoustic sound insulation. The relatively low stiffness of a straw-bale wall with earthen plasters is ideal. The fact that the cavity between the two plaster shells is filled with straw provides excellent acoustic damping. Beware and be careful to fill all cavities and voids with very light straw/clay. Avoid any direct mechanical contacts between the inner and outer plaster shells, as these will seriously degrade sound damping performance. Contrary to what you would expect, loosely packed bales will perform better than very tightly packed bales. Extra thick (>35mm) earth plaster specifically improves low-frequency performance. Cement and lime plasters perform almost as well but earth plaster with lots of straw is the best due to a lower modulas of elasticity (stiffness). Applying significantly asymmetrical plaster thicknesses helps to avoid coincident reverberation of the inner and outer plaster layers. The thicker plaster layer should be on the sound source side of the wall. Pay a lot of attention to all openings and edge details; these are the weak points. An air leak of only one sq. mm will seriously degrade performance. Door openings and windows are literally acoustic holes in the wall; these need special detailing and attention to even remotely approach the acoustical (and thermal) performance of the surrounding walls. Even double doors generally show poor performance compared to the wall. The gaskets and seals in the doors should be double or even triple, but even then there is a problem as, over time, the seals will degrade and leaks will occur. The type of door you are aiming for is more like a steel watertight door in a ship than a house door with multiple closing bolts and tightening clamps. (All of this only if acoustical performance is essential.)

table2In conclusion, I would like to emphasize that, due to the nature of a straw-bale wall (an excellent sound barrier), the wall is not the problem; the connections between the

wall and all other elements incorporated or surrounding it are. In other words, it is the same issue as with thermal and moisture performance. I strongly suspect that most sound isolation tests executed on straw-bale walls are measuring the defects of other structural components or mistakes in the test procedure (a non-calibrated sound source, background noise, and such).

Room Acoustics

Here are some simple rules of thumb depending on the type of acoustics you want, e.g., very lively to very well damped. Soft acoustic instruments require a “live” (reflective) room. Loud amplified sound needs a “dead” (absorbtive) room. The single most important parameter is the reverberation time and level. The harder the surfaces, the livelier the sound. A bathroom is lively, hence your strive to sing even if you can’t. The opposite is standing on top of a snow-bound hillock [small hill or mound] – virtually no sound reflects back to your view. The bigger and harder the room, the longer the reverberation time, e.g., a cathedral. Next the relative dimensions: an oblong box (like Concertgebouw Amsterdam) approaches the ideal. Preferably the relative dimensions are approximately 2 to 3 to 5; this ratio will avoid the formation of dominant harmonic resonance and standing waves. The exact ratios needed for a given acoustical requirement depend on the size and acoustic reflectivity. I personally prefer rooms without parallel surfaces, thus avoiding standing waves. I think if you finish a room with earth/clay plaster on straw-bale walls, with wooden flooring and a well-pitched ceiling, you will have quite acceptable acoustics for musical performances. If it’s too lively, you can always add some damping afterward by placing soft furnishings in the room or hanging curtains on the windows. A bigger audience also helps.

Good acoustic isolation is definitely one of good merits of straw-bale walls. It should be seriously considered for purposes where sound isolation is of importance. It would be hard to find a more affordable solution to building sound studios, quiet houses in noisy neighborhoods, or noisy workshops in residential surroundings.

<[email protected]>

Rene Dalmeier has been interested in straw-bale building since 1998. In June 2005, he finally took the plunge and turned his hobby into a profession by becoming a full-time straw-bale builder.

A whisper = 15 dB … Normal conversation = 60 dB. dB: Abbreviation for decibel(s). One tenth of the common logarithm of the ratio of relative powers, equal to 0.1 B (bel).

House of Straw? – Reprint from TLS #57

By Bales, Design, Straw Bale Construction 2 Comments

 

build-our-house-out-of-straw2Build our house out of straw?

by Stephen MacDonald – New Mexico, USA

This article appeared in The Baley Pulpit,TLS#7/Summer 1994.

“May we look upon our Treasures, and the furniture of our Houses, and the Garments in which we array ourselves, and try whether the seeds of war have any nourishment in these possessions, or not.”

– from the Journal of John Woolman an 18th Century Quaker

“Build our house out of straw?” When our neighbor suggested the idea as a solution to our housing problem, both my wife, Nena, and I reacted similarly. “You must be kidding!” Even when he showed us a copy of Fine Homebuilding with an article in it by Gary Strang (1985) on a studio built out of straw bales, we were dubious. It was just too weird (images of rotting hay, mouse hotels, and pig stories readily came to mind). The idea was too simple and straightforward to be believed.

Try as we might, however, we kept returning to the idea of it. It did seem to fit our condition: Using straw bales was 1) low cost…we were near broke, having used the last of our meager savings to buy a small piece of land; 2) a way to stay cool (and warm)…having just moved to southwest New Mexico from Alaska, I was scared to death of the heat; 3) fast and physically easy to build…I just couldn’t face the slow, heavy work of adobe; and 4) ecologically sound…besides being energy efficient, a straw-bale building uses a renewable resource (often viewed as a waste product) that was locally available. Done right, building with straw uses very few trees.

In the end, we decided to go for it. Seven years later, we have no regrets. Just the opposite. We didn’t know it at the time, we were not the only ones interested. Through Strang’s article and newly formed friendships with Susan Mullen, a permaculturist and close neighbor, and an enthusiastic Matts Myhrman in Arizona, we learned of a small but dedicated network of straw-bale aficionados. Nor were any of us particularly innovative. The true trailblazers of straw were the folks from the Sandhills of Nebraska who, out of necessity, started a tradition of building their homes out of native hay and straw beginning back in the late 1800s and continuing up through the early 1940s.

The work of the Nebraska homesteaders remains the key. It took a fact-finding journey to Nebraska in 1989 by Matts and Judy Knox, his wife, to finally convince us that we, like most of those early Nebraskan straw-bale builders, could further simplify our technologies by using straw bales as load-bearing walls without the time and expense of poles or posts. We modern practitioners of straw have come to call it building “Nebraska style.”

It is this style of building that has captivated my imagination and been the thrust of our most recent building endeavors. Much good work needs to be done to revitalize the straw-bale building tradition and get it accepted into common practice. Tackling the building codes is part of that work along with trying (and sharing through The Last Straw) new and innovative techniques. I have no doubt in my mind that sooner, rather than later, this Earth will demand it of us.

 

 

Nena in front of the MacDonald’s straw-bale home.

Nena in front of the MacDonald’s straw-bale home.

Meanwhile, here are some of this straw-bale builder’s rules of thumb.

I. Keep it small. How much space do you really need? Be honest. Be creative with your space. Small is easy to heat and keep cool. It’s easier to keep clean. It takes up fewer of the earth’s resources and takes up less of its space. You finish the job, at a lower cost, so you can devote money and energy to more useful work. If your teenagers need distance, have them build their own outbuilding or addition. They need to learn the skills, anyway.

2. Keep it simple. Control your impulses to make your house a complicated, “artsy” statement. Simple, small and rectangular houses are beautiful when made of straw and other natural materials. Let form follow function. Again, spend all the time and money you saved by being – out in the woods, feeding the poor, or playing with your children.

3. Build it yourself. Trust yourself. You can do it, especially if you build with straw…and especially if you follow rules 1 and 2. Read building books and magazines.

Ask questions of builders. Build it on paper and as a model first. Track the details. Use your common sense. Be creative with your mistakes. Don’t be intimidated by the “experts.”

4. Stay out of debt. Pay as you go. Assemble the parts as you have the money and time.

5. Use local materials. Use more rock and adobe. Use locally milled lumber and poles. Your neighbor needs the work and you need to know firsthand what demands you’re asking of the forests and the fields.

6. Be energy conscious. Build to maximize passive heating/cooling strategies. Superinsulate your ceiling. Stay off the electric power grid if you can. Put up a windmill or use a solar pump. Build a composting toilet. Raise a garden.

7. Make yourself a home. Don’t just build a house, make yourself a home. Learn to be at home. Do no harm.

6 June 2005 Update

It is hard to believe that 18 years have somehow flowed by since Nena and I first built our little house of straw here in rural New Mexico. Two kids fledged, one now married and making his way at the edge of the Adirondacks in New York, the other just back in the United States after months of solo travel through Europe and western Russia.

Our little house continues to do well. We finally added a small greenhouse to the southwest corner of the place, and several years ago built a really first-class outhouse off the shop. I keep meaning to replace the salvaged (and very inefficient) casement windows we have, and one of these days I’m going to get around to finally plastering the outside of my Nebraska-style office/former teenage daughter ‘cabin.’ “Margosh, margosh” as my Mongolian friends would so often say – tomorrow, tomorrow.

Stephen MacDonald lives with wife Nena, son Orien (and co-author with his father of A Straw-Bale Primer), and daughter Aili, in their owner-built houses of straw in Gila, New Mexico. Steve and Nena live their Quaker faith in numerous ways including active participation in The Friends of the Gila River, working to create a cooperative ecosystem-based Gila River Ripiarian Management Plan with all stakeholders. Steve returns to Alaska each summer to continue biology mammology field work in the bush, and touch base with his northern home for over 14 years in the 1970s to early 80s… and stay cool.

“Somehow Nena and I have survived our various mid-life crises, finding new balance as we age and continue along our now 32-year journey together. I am still very much engaged with my work on far northern mammals (now through the Museum of Southwestern Biology), while Nena, having let her nursing license lapse, spends her days here at home.”

[Guest Editor’s Note. Stephen and Nena’s small straw-bale house has been an inspiration to many. It still inspires because it so effectively embodies the basic principles Stephen outlined of what a home should be a nice place to live in.]

Post Editing Note: If this information is valuable to you, there is much, much more in the published, official version of The Last Straw.  Please subscribe at The Last Straw online.

Sill Pan Design Detail – TLS #51

By Bales, Straw Bale Construction, Technical, Walls No Comments

 

Slope pan flashing to outside.

Slope pan flashing to outside.

Included in TLS #49 (Myths and Realities, Spring 2005) was a discussion of ways to deal with moisture at the bottom of windows. David Eisenberg shared a written design detail for a pan under the window to carry water away from rather than down the wall. We wanted to share a drawing of this detail and David kindly provided one for us to share in Tech Tips.

Here’s the portion of the discussion in which David details this design idea.

“Protecting the bales beneath the windows requires that you catch the water under the window and make sure it gets all the way out of the wall. In other words, ideally, you would have a pan of sorts under the window, sloped slightly to the outside, extending a bit beyond each side and with a lip at the back and on each end (so water can’t just run off the ends), and extending out beyond the exterior wall surface, with a drip edge – so that any water that leaks through or runs down the sides of the window ends up in this pan and is shown the exit. You can make these pans out of metal, plastic, ice and water shield, cast this shape into a concrete sill, anything that will keep the water from leaking through it, but the principal thing here is to make sure that the water can’t get into the wall below the window. You can put your window sill material, whatever it is, on top of this pan flashing being careful not to punch unsealed holes when you install the sill. It can take a little thought and ingenuity to do this, but it assures you that, when the windows leak, the water leaves the building.

sill2

Concept of pan flashing turned up at back and sides extending beyond exterior finished wall with drip edge. Extending behind finish or trim at each side of opening.

“That old practice of just putting roofing paper or plastic over the top of the bales and setting your windows on it and then plastering over it just leads the water down inside the plaster to the bales wherever the water protection ends unless it runs continuously down the wall under the window to below the bales (and we don’t recommend doing that).  It just temporarily moved the problem down, didn’t solve it.”

Panel-built Classroom in Northern Arizona

By Bales, Design, Products, Walls No Comments

This article originally appeared in TLS #49.  Articles on straw-bale wall panel systems are included in issues #30, #42, #47, #48, #55.

panels1-300x224by Matt Robinson – Arizona, USA

Northen Arizona provides an ideal climate in which to build with straw bales and has been the site of many such structures since the 1990s. Ed Dunn has been the principal designer and builder of straw-bale homes here for over a decade. In May‘04, Western Strawbale Builders (WSB) was formed by Jason Radosevich and Matt Robinson, former crew members of Ed Dunn. The focus of WSB is to increase the scope of straw-bale building to include affordable housing as well as top-of-the-line custom housing.

With affordability in mind, systems using prefab panels seem to us the most promising avenue of approach to building with straw bales. In order to spare you the well covered details of this method of building, you can reference several articles published by TLS including: Chris Magwood in TLS#42, Canada Guy TLS#47, and Brett KenCairn in TLS#48.

Western Strawbale Builders was able to show off our skills in a project this past Fall here in Northern AZ. Designed and overseen by Ed Dunn, this project was an additional building done for The Star School, an off-grid solar-powered charter school on the borders of the Navajo Reservation in Coconino County. Star School teaches middle school students subjects, including permaculture, cultural awareness, and sustainability. Proprietors Mark and Kate Sorrenson therefore wanted to build a structure that reflected these values while fitting into their budget.

Ed Dunn designed this structure to utilize passive solar principles, trombe walls and a greywater planter. It is to be used as a combination classroom, performance hall, and wrestling gym, as well as any other creative uses Mark and Kate come up with.

We decided to hold the bid on this project to the regular bid price for stick-framed structures in our area to see how well we could compete. To our mild shock and great relief, we were able to build to these numbers and still afford our business a modest profit. With a four-man crew including ourselves and the exceptional abilities of carpenters Alden Catherman and Phil Mason, the class room was completed in eight workweeks, beginning to end.

We feel that this project, although relatively simple in scale and design, can serve as an example of an affordable option for people who love the idea and feel of straw-built houses. Hopefully this structure and others like it will help in bringing straw-bale houses into the mainstream.

Matt Robinson and Jason Radosevich own and operate Western Strawbale Builders in Flagstaff, AZ. Contact: or westernstrawbale.com

A Bit About Bale Walls

By Bales, Straw Bale Construction, Walls No Comments

Currently in rough draft form, this information is the beginning preparation for an article or perhaps two that will appear in a future issue of The Last Straw journal with the theme “All About Bales.” Your comments and input are welcome.

by Joyce Coppinger, Managing Editor/Publisher, The Last Straw Journal

Wall Structures
The structural methods used for the design and construction of bale walls are generally of two types: loadbearing and non-loadbearing. Stated another way – bales supporting the weight of the roof and any snow or other roof loads, and any post-and-beam or modified post-and-beam structure with the bales used as infill for insulation only.

Timberframe is the post-and-beam structure of choice in most countries. Posts of conventional milled 4×4, 4×6 and 6×6 wood; lodge poles, timber bamboo and other types of materials have been used. Modified post-and-beam structures are wide-ranging and diverse – anything from box columns to ladder-truss wall systems, to the current experiments in and development of SIP or structural insulated wall systems (also called wall panel systems or panelized walls) using bales as the insulation material rather than rigid foam insulation as the material sandwiched between the sheathing on both sides. [See articles in TLS#42 and #55.]

Widths
Bale walls come in many different widths depending on the size of bales you use, how you lay the bales as you stack them, and even the type of material baled and the method used to stack the bales to form the wall.

Widths Using Small Square Bales: Typical widths for bale walls are 16 or 18 inches when the bales are laid flat (strings or wires on the top of the bale). If stacked on edge, the bale width will be 14 inches with the strings or wires on the side of the bale. If the bale is stood on end to fill a framed space, the bale can be either 14, 16 or 18 inches depending on the size of the bale and the direction in which you set the bale.

Size of Bales
Even though a bale may be called “square,” it’s usually rectangular in shape.

The size of a small square bale may vary by region or country depending on the type of baling equipment used or the method of making the bale, e.g., bale press or hand pressed compared to using a mechanical baler. The bale may also vary because of the type of mechanical baler used and how it’s set to produce a bale.

The small and medium size balers used in some regions of the U.S. have a fixed bale chamber that produces a bale that is 14-in.x16-in., 14-in.x18-in. or 16-in.x18-in. The length can be varied to produce bales between 36 inches and 41 to 48 inches. This is the range of length that is required by most automatic bale wagons used to pick up bales in the field in the U.S..

You should also be aware that there are also other sizes of bales used – some are called “jumbo” bales because of their large size. In some places, these large bales might be called 4x4s or 6x6s or 8x8s. Some people define a square bale’s size as small, medium and large. Small bales can be 24in.x24in.x48-in. Or they can be 14-in.x 16 to 18 in.x 36 to 48 in. A medium bale of this type is around 4-ft.x4-ft.x6-ft., and large bales around 6-ft. to 8-ft. square by 8-ft. to 10-ft. long. Weight depends on the type of hay and settings of the baling equipment.

And density (compactness of the baled material) or compression (how much pressure is placed on the bales to “compress” them when they are created or after they are stacked) of the bales might also change the dimensions.

The binding material on the bales is most often wire or poly twine; sisal (natural fiber) isn’t the best to use as it tends to break while the bales are being handled. Some people don’t use wire as they are concerned about moisture might condense on it or be drawn to it; some feel it’s difficult to work with when retying bales, others feel it’s easier. Some don’t like to use the poly twine because of the coating or because they feel it’s not as easy to work with. In most cases ot comes down to personal preference or type of binding available locally.

Placement of Bales
Bales laid flat are usually 16 to 18 inches wide and 14 inches high; they can be 36 to 40 to 48 inches long. Bales stacked on edge are usually 14 inches wide, 16 to 18 inches high, and the same lengths as mentioned for bales laid flat. Bales used to fill in framed spaces – or stacked on end – can be 14, 16 or 18 inches wide depending on how you orient the bale in the space filled.

There has been and continues to be much discussion about the way bales are laid or positioned when stacked. Are bales set on edge or bales laid flat easier to plaster, and what reasons do balers use to explain a preference for one method or the other? Do the bales laid flat have less or ore insulation value – and why?  Do bales set on edge have more tensile strength than bales laid flat?

What to Use and What Not to Use
A bale made with a mechanical baler that chops the straw as the bales are made probably doesn’t produce the best bale for construction – it tends to fall apart or could be harder to work with when cutting and tying.

A bale made from alfalfa will be hard to use – the alfalfa tends to be woody and brittle, the bales are usually not uniform in shape and perhaps even in size to some extent. This may be true of bales made from switchgrass or flax or other “slippery” materials.

Bales made from tumbleweeds are not suitable for bale building – they are very brittle and highly flammable (usually very dry). The same could be said for pine straw bales – the kerosene in the pine needles is flammable and the pine needles are also one of those “slippery” materials mentioned earlier.

The most common materials used for buildable bales are wheat, oats, rye, rice, and hemp. It’s said that the Nebraska prairie pioneers used prairie meadow hay (probably hard to find these days), cattails and wetland reeds (most often baled during droughts). We’ve heard of the use of bales made with timothy grass, Sudan grass, and barley. We’ve been asked about corn stover and soybean stover – but don’t know of anyone who’s ever used this crop residue as a bale building material. If you’ve heard of other materials used for buildable bales, please let TLS know.

Fire in a House With Straw Bale Walls

By Fire, Straw Bale Construction, Walls One Comment

This article is original content and has not yet appeared in the printed version of The Last Straw.

No, this is not the house.  We dont have a picture of a bale house on fire!

No, this is not the house. We don’t have a picture of a bale house on fire!

This story is a reluctant one about a house comprised of both wood-framed and straw bale walls lost to a fire in 2009. The structure was built over a longer period of time than most main-stream homes.  The different phases incorporated the most appropriate materials at the time for the owners. We are excluding specific reference to the owners and the location of the building due to privacy concerns. For this article we will say that the building is in the central U.S. at approximately 8,000 ft elevation and the Owner’s name is Bob. In the end, it really does not matter who owns the home or exactly where it is. What we will focus on is the performance of the bale walls in the fire, the aftermath, and how the owners and insurance company feels about the whole incident.

The building was an un-permitted residence in a rural mountainous area. As mentioned above, some of the walls were wood-framed, others were built with bales. The bale portion of the structure was round, approximately 26′ in diameter, on a foundation that was an 8″x18″ concrete grade-beam supported by concrete pillars, with a yurt-style roof which included a “tension-ring” cable. The bale walls were Nebraska-Style (no posts) and had a 2×6 box-beam for the top plate with plywood on the bottom but not the top. The box-beam was filled with rigid foam insulation. Both the interior and exterior surfaces of the bale walls were covered with cement-based plaster. Two coats were present on the exterior and one coat was completed on the interior. There were relatively small areas not plastered on the interior, but the location of these un-plastered areas were not specified in my conversation with Bob.

The fire was started in the crawl-space of the framed portion of the structure by accident. It quickly spread throughout the framed structure and overtook the occupants who had to flee for their safety.  Bob is a local volunteer firefighter who was overcome with smoke inhalation and had to be taken away for medical care. He was present for a majority of the fire and taken away before it was extinguished. However, he has some interesting comments regarding the bale walls, how they performed and how they were affected by the fire. The family lost everything to the fire and is now picking through the remains.

The fire quickly engulfed all of the wood-framed structure and spread to the floor and then the roof of the round bale structure. The roof of the round structure collapsed inside the bale walls but the bale walls themselves were still standing when the fire department , hampered by by the long driveway and 18″ of fresh snow, arrived on the scene 50 minutes after the fire started.   Due to smoldering straw the fire department felt compelled to knock the bale walls down to access smoldering area within the walls.  Eventually all the bale walls were knocked down and all of the smoldering extinguished. This process took five days after the initial incident.

Bob commented about how fast the areas with no plaster ignited compared to the bale walls covered with plaster. The windows and doors had been framed using standard wood bucks. These, in addition to the wood box-beam, became the main avenues for the fire to spread into the bale walls. It appeared that the fire moved down from the top and in from the window and door bucks. Had these areas been plastered, or concrete bucks used, Bob feels the bale walls may have been spared.

Due to the generally impenetrable nature of the walls they seemed to act as barriers to heat-flow in both beneficial and detrimental ways.  Bob had installed his solar PV array 10 feet from the bale structure. The PV panels were virtually unharmed due to the shielding nature of the bale walls. His wood-framed shop, situated approximately 30 feet from the framed portion of the residence, ended up burning to the ground from direct exposure to the heat of the fire. The drawback was that Bob felt the bale walls created an oven-like effect within the building, holding heat inside, keeping the temperature very high.  As a result, one of the losses was the family safe which was supposedly fire-proof.  It was unable to withstand the “heat-trap” surrounded and created by the bale walls.  From these accounts, It is clear that the bale walls have a very significant heat-shielding effect during a major fire event.

The entire structure was insured by Allstate Insurance.  Bob was honest with them at the time of insuring the building and did not hide the fact that part of the building incorporated bale walls.  Allstate did not seem to make a big deal of the fact either then or now.  It appears they are making a pay-out on the insurance policy.  This is good news to bale building owners everywhere.  An insurance company had the capacity to not focus on the fact that some of the exterior walls were made of straw and plaster.  It is not clear if they understood how stable the walls were during the fire since they did not collapse, like the rest of the structure.  The fact that the bale walls did not contribute to serious problems was probably one reason for the lack of focus.

Being a volunteer firefighter Bob was frustrated he could not help fight the fire that destroyed his own home.  He understood that following orders from his fellow firefighters to seek help for his smoke inhalation was the right thing to do.  When asked about how the fire was suppressed in the bale walls and why it took so long, it became clear that the ongoing smoldering was not going to stop on it’s own.  The walls needed to be broken up in order to access all of the smoldering spots.

It seems that there is a pattern among bale buildings that are engulfed by flames.  The walls remain standing as long as anyone is willing to let them stand.  The main reason they are taken down is to gain access to smoldering areas within the walls so as to eliminate any risk of spread and the accidental ignition of other fires elsewhere.  The fact that bale walls are very effective heat shields makes them good fire-separation wall candidates between living units, or uses, within a structure.  They remain stable throughout the fire event, which cannot be said of steel or wood-framed walls in low-rise residential or commercial construction.  The fact that they tend to smolder and require maintenance for days after the initial fire event costs money and resources, but weighed against the fact that they do not fail catastrophically means that they may be considered as life-safety elements in buildings with many uses and occupancies.

The lessons learned in this building are that bale walls are incredibly stable during a fire event, offer a thick shield to retard flame-spread, and are tough to dismantle, requiring many days and resources by the local fire department.  When put together it seems that the bale walls themselves had a much better track record than any other part of the structure.  Feel free to comment or add to the discussion by logging in and submitting your thoughts.

Bob says he will not rebuild with bales mainly due to the huge amount of labor involved.  He will probably choose to build with some form of ICF (insulated concrete form) and steel.  He and his family enjoyed their bale home, but the time and labor necessary do not seem as realistic the second time around.

All fires in bale buildings are felt throughout the community as a serious and deep loss.  Even though we do not wish for them there is a great deal to learn from each and every one.  We hope this account will help firefighters, insurers, designers and homeowners make the best decisions possible.  Please comment below and participate in the conversation.  We are interested in your thoughts.  Email the author with any specific question for the owner offline.

Where to Draw the Line – TLS #50

By Bales, Design, Technical No Comments

This article appeared in TLS #50.

by Chris Newton – Queensland, Australia

Can you design and build straw-bale homes for a hot and humid climate? Living in Queensland, Australia, I am frequently asked to identify an invisible line on the map where “she’ll be right” applies on one side of the line and “don’t go there” applies to the other. The part of me that fears litigation wants to respond with “ask me in 20 years time,” the technical part of me feels it has to be evidence based, and the logical part knows the answer already exists in the local environment. So I take on board here these three points and discuss how I attempt to find that line on the map in our building history, current research and the observation of the environment we live and build in.

Macro Climate

Queensland extends from 10 degrees south to 29 degrees south of the equator, covering more than 1.72 million square kilometres. Queensland is more than twice the size of Texas. Within Queensland, we live in monsoonal, tropical, subtropical, grassland and desert climate zones.

The table below represents summer (December though March) in the climate zones of Queensland. Summer is dominated by the monsoons making this a hot, wet and humid season. All zones in Queensland have mild and dry winters.

Microclimate

table3We can create a microclimate in and around our homes. Changes in air movement, moisture load or sunshine can significantly change the wetting and drying potential of a section of the building. When designing the house and gardens in a humid climate, we need to be aware of creating microclimates that cannot dry out.

Relative Humidity

Humidity is the water vapour held in the air. This is the ratio of the actual amount of water vapour in the air to the amount it could hold when saturated; it is expressed as a percentage. The capacity for air to carry water vapour increases as the air temperature increases. Air with a temperature of 30°C/86°F can hold more than three times as much water vapour as air at 10°C/50°F.

The dew-point temperature is temperature in which air must be cooled in order for dew to form. Droplets of water can be deposited within the straw-bale wall when air cools below the dew point and water vapour condenses.

Wood can absorb moisture content up to 25% from a relative humidity 98% (See Straube report in Resources at end of article). Straw is hygroscopic with its large surface area and internal pores having the ability to absorb moisture. A bale whose moisture content is at 8% will weigh less than the same bale with a moisture content of 20%.

 

Wetting Potential

graph

Table Daily Humidity in relation to Temperature Changes Source: Australian Bureau of Meteorology

We have a copy of an 1860 encyclopedia. It’s only damage is some yellowing and a few small brown spots (mold). This book had no special storage other than to sit on a bookshelf in subtropical Brisbane. So it seems that humidity alone may not be enough to cause decomposition of straw bales. However, I know through talking to people from Cairns that it is the norm to have molds growing on curtains, furniture and shoes throughout their summer. Newspapers and photos curl from the moisture they absorb. So humidity alone is enough to support mold growth in the tropics.

Historically, bathrooms have remained an area with high failure rates from moisture; this is true in any building type. Protection for straw-bale systems in wet environments exists. This can be in the form of vapour barriers, water barriers, design considerations, and attention to detail. It would be fair to say that, over the life of a building, some houses despite best efforts will experience elevated moisture levels in part of the wall system. Concentrated moisture only becomes a problem if the ability to dry is not timely for the given climate conditions. Remember that molds grow rapidly in hot and humid conditions, and are dormant in cold conditions.

Drying is the balance for wetting. The measure to ensure this includes a capillary layer below the bottom straw bale and a render with high permeability. Water vapour moves from low concentration to high concentration. High humidity will reduce the ability for the wall system to dry. In the tropics, rain may persist over several days. Attempting to dry clothes in the shade will take a long time during which they will acquire a moldy smell. You can not expect a wall system on the south side of the building to dry as efficiently as those on the north. High humidity will further compound this. (Note that we live in the southern hemisphere.)

Can you build with straw bales in a high humidity climate?

The line that removes high risk for straw-bale construction is unlikely to be a latitude line. Maybe it is a line that farmers have already identified. Grain farmers look for a climate dry enough so the grain dries adequately before harvest. The dry grain is then suitable for storage. Humidity is not a problem for the sugar cane growers who harvest the crop with high moisture content and send it straight to the mills where the juice is squeezed from the cane. So maybe the invisible line is found on an agricultural plan.

Resources

How Straw Decomposes, Matthew D. Summers, Sherry L. Blunk, Bruan M. Jenkins. www.ecobuildnetwork.org/pdfs/ How_Straw_Decomposes.pdf

Straw Bale House Moisture Research, CMHC (Canadian Mortgage and Housing Corporation). www.cmhc-schl.gc.ca/ publications/en/rh-pr/tech/00-103-E.htm

Moisture Properties of Plaster and Stucco in Strawbale Buildings, Dr. John Straube. www.ecobuildnetwork.org/pdfs/ Straube_Moisture_Tests.pdf

Monitoring the Hygrothermal Properties of a Straw Bale Wall, Dr. John Straube and Chris Schumacher. www.ecobuildnetwork.org/pdfs/Monitoring_Winery.pdf

Bureau of Meteorology–Australia. www.bom.gov.au/ weather/qld/

Chris Newton, Earth-n-Straw, Queensland, Australia, 0413 195 585, <[email protected]> www.newtonhouse.info. Chris, an owner/builder, educator and trainer in strawbale, plasters and other aspects of natural building, is the new President of AUSBALE, the Australia and New Zealand straw-bale building association.