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Straw Bale Construction

Articles on Straw Bale Construction

Being probably the most querried topic within natural building on the internet, straw bale construction has become what some people refer to as a ladder or bridge technology.  It is an easy path for people to follow and understand who are new to such a vast and under-utilized family of construction techniques and systems in this modern age.

The Last Straw was founded as a response to the need to disseminate information primarily about bale construction, but soon broadened its scope to include the entire natural building world and beyond.  You will find a wide range of topics on this page related to straw bale construction and probably more related systems to explore.  Ask questions in the comments section of each article and browse multiple pages to find what your seeking.

 

Red de Construcción con Paja

By Bales, Community, Issue 62, Straw Bale Construction No Comments

logoRCPBIENVENIDOS, we’re the Spanish-speaking straw bale network RCP (Red de Construcción con Paja), or Network of Building with Straw.

The RCP network of straw bale construction is a non profit organization with about 75 active members, but with a lot of fans. Our webpage has more than 7,000 visits a month.

RCP is now 8 years old, as it was born 2005 in Barcelona, Spain. Only couple years later our little magazine, in 2007, “BRIZNA” was printed for the first time where we document our straw bale building experiences twice a year.

The aim of RCP is to be open and to support other Spanish speaking countries to spread the word, especially if they do not have their own network. That’s why we don’t call ourselves the Spanish Straw Bale Network.

Book Review: Earth Render

By Issue 62, Plaster, Straw Bale Construction, Technical, Walls No Comments

Reviewed by Jeff Ruppert

Cover file  SmlEarth Render: The art of clay plaster, render and paints by James Henderson is a refreshing, easy approach to what can become an overwhelming process.  As anyone knows who has worked in the natural building trades, earthen materials are highly variable and therefore require a basic understanding of those variables.  James Henderson explains this process in a concise, easy-to-read format with plenty of illustrations.

What is nice about the approach of this book is that it is meant for the novice as well as the seasoned tradesman.  It can be followed by anyone and needs little introduction.  It focuses on how earthen materials are used to clad and finish walls, and that is it.  There are no lengthy chapters espousing the virtues of earthen construction.  Mr. Henderson assumes that you are reading his book to learn the finer points of his trade, and therefore an ethical discussion is not necessary.

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Traditional and Contemporary Natural Building in Korea

By Bales, Design, Energy, Floors, Issue 62, Plaster, Straw Bale Construction, Straw-Clay, Walls No Comments

By Kyle Holzhueter

Editors Note – This article is a feature length pictorial look at the various aspects of natural building in Korea.  The full-length article will be in the upcoming issue of The Last Straw and is available in its entirety right here on the website for subscribers.  Make sure you have a subscription soon so you won’t miss this stunning array of natural building techniques.

Traditional Korean Architecture

Traditional Building in Korea relied primarily on natural and local materials.  Buildings were traditionally designed according to the 間 (Korean: ka, Japanese: ken) module, a common measurement found in east Asia.

East Asian Modual

East Asian Module

Traditional Korean homes generally have a timber frame with adobe or wattle and daub infill, though regional variations are found throughout the country.

Traditional House

Traditional House

Regional Variation

Regional Variation

Especially on Jeju Island where volcanic rock and strong winds are abundant, homes traditionally consisted of a double wall system with an exterior wall of volcanic rock surrounding an interior wall, creating a protected corridor around the house.  This in turn, protected the interior walls from wind and rain and improved the thermal performance of the home.  Also because of the strong winds, thatched roofs were generally secured by a net of straw ropes.

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A Strawbale Residential Building Code for the United States

By Bales, Codes and Permits, Issue 62, Straw Bale Construction, Technical One Comment

By Martin Hammer

Mark, Martin, David and  Laura with ICC sign

Mark, Martin, David and Laura with ICC sign

October 14, 2013 marked an historic day in the history of strawbale construction and natural building.  A proposed appendix on Strawbale Construction, and a separate appendix on Light Straw-Clay Construction, were approved at the International Code Council (ICC) Final Action Hearings in Atlantic City, New Jersey.  Both appendices will be included in the 2015 International Residential Code (IRC) for one- and two-family dwellings.  (See sidebar regarding the Light Straw-Clay appendix.)

This has far reaching implications, because the IRC is the basis for the Residential Building Code in virtually every jurisdiction in the United States.  In addition to making permitting easier, obtaining financing and insurance through conventional channels is expected to become much easier, because concerns about structural capacity, fire resistance, moisture issues, etc. are clearly addressed in the code

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Adsorption (More Building Science)

By Bales, Building Science, Issue 62, Straw Bale Construction, Technical No Comments

Building-ScienceBy Chris Magwood

An important concept to understand when considering moisture and building materials is adsorption. Moisture in vapor form infiltrates any and all materials. The surface of most materials will offer individual water molecules an electrically charged attraction, and the water molecules will “stick” to all available surfaces. The makeup of plaster and of straw bales offers a vast amount of surface area for this adsorption. Plasters are full of micro-pores and straw has great deal of available surface area as well as micro-pores in the hollow stems. Together, these materials allow a surprisingly large amount of moisture to safely adsorb onto/into the materials without the water molecules accumulating in sufficient layers to become drops of liquid water. Bales and plaster can hold a remarkable amount of moisture in adsorbed form. “For a 8 pcf (pounds per cubic foot) bale, more than 1 pound of water (approx. 1/12 gallon or 0.46 liters) in vapour form can safely be stored per square foot of wall area” according to John Straube in Building Science Digest BSD-112. This explains why the walls can perform so well as “vapor open” or “vapor permeable” systems.

Straw Bale and Building Science: Growing Up Together

By Building Science, Design, Energy, Issue 62, Plaster, Straw Bale Construction, Technical No Comments

by Chris Magwood

Making Things Air-Tight

Making Things Air-Tight

The straw bale revival of the 1990s reintroduced builders to a pioneer building method that showed remarkable potential for building in a modern context. The nature of the basic components of a straw bale wall system – bales with plaster applied directly to bales – combined several obvious advantages over other wall systems while simultaneously raising some serious questions.

The advantages are familiar to TLS readers: low environmental impact, simplicity and well placed thermal mass. The serious questions and attempts to answer them were the lifeblood of TLS: What about moisture? Air tightness? Cold climates? Humid climates? Longevity of the straw in all these conditions?

There was a lot more going on in the construction world of the 1990s than the straw bale revival. The housing industry was recovering from multiple moisture-related disasters, many caused by overly airtight but under-ventilated homes and/or the use of un-vented “waterproof” exterior cladding systems. The research into these issues, among other factors, led to a rise in prominence of “building science” as a distinct engineering discipline. The straw bale revivalists were extremely lucky to have the attention of some of building science’s leading practitioners, in particular John Straube, who authored several key articles and studies about straw bale walls that were essential to answering the question of why bale walls were so resilient, despite some seemingly obvious moisture concerns.

Simply put, building science attempts to quantify the movement of heat and moisture through building assemblies and help designers and builders to make decisions that lead to structures that adequately deal with the moisture and temperature regimens of their particular climate and use.

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Straw Bale Construction Building Code (2013 IRC Approval)

By Codes and Permits, Issue 62, Straw Bale Construction, Technical One Comment

codes1A more recent post with a more in depth explanation of the ramification of this code appendix can be found here.

On October 14, 2013 the International Code Council (ICC) approved final action RB473-13 as a new Appendix R in the upcoming 2015 version of the International Residential Code (IRC).

The approval marks the latest advance of straw bale construction in the building codes and permitting process.  It is the highest approval to be granted for the construction method and will be adopted by thousands of jurisdictions around the United States in and after 2015.

The process of creating the IRC appendix was spearheaded by Martin Hammer of Builders Without Borders representing the California Straw Building Association, the Colorado Straw Bale Association, the Straw Bale Construction Association –New Mexico, the Ontario Straw Bale Building Coalition, the Development Center for Appropriate Technology and the Ecological Building Network.

Thousands of hours of work have been donated by Martin and various individuals within the straw bale construction community to make this milestone a reality.  We thank all of them for their hard work and look forward to even more widespread acceptance of straw bale building in the construction trades.

A copy of the approved appendix can be downloaded here:

IRC_StrawbaleConstructionAppendix_Approved_10.4.13.pdf

 

Feuillette House

By Bales, Community, Issue 62, Straw Bale Construction One Comment

Update: The Feuillette House has been purchased by the Centre National de la Construction Paille.  They are still in need of support to complete their plans for creating a visitor center at the historic site.  

While Nebraska makes the claim for the origins of bale construction, the French have an excellent example of historic straw bale construction in Montargis (see map for location).  The Feuillette House is up for sale and the Centre National de la Construction Paille (CNPC, National Center for Straw Construction) is leading the effort, in partnership with the Centre Preservons Aujourd’hui L’avenir (Centre for Preserving the Future Today), to purchase and preserve the house, while also performing research that will help all of us understand the origins and background of this unique building.  

What we have been able to determine, in addition to what is on the website shown below is that the house is built over a partial masonry basement.  It appears to be a great old example of multiple floor and foundation configurations from the distant past.  

Other notable components of the building include the plasters and framing system.  Lime render was used on the exterior and gypsum on the interior.  The frame is very similar to what you would see on many modern straw bale construction projects, using 2x material to create full-depth posts.  This building is considered the oldest post-and-beam straw bale building in the world.

Maison-Feuillette-CNCP-1920-2013It also appears that infrared images have been taken of the house to show it’s thermal performance as shown in this document, which is partially translated to english.

At this point, according to Fabienne Pasquier, Communication Manager at CNCP – Feuillette, they have raised 65,164.8 € towards their 70,000 € donation target.  This money will be part of the 270,000 € budget for purchase and research.  They are very close to achieving their goals and could use help making it across the finish line.  A direct link to make donations by credit card can be found here with the english translation here.

According to their website “The “maison Feuillette”  was built in 1921 by Feuillette, an engineer who was looking for solutions to construction problems following the war. The house is at Montargis, 90kms from Paris. It has been for sale for one year.

On a plot of land 1500m2, the 2 storey house covers 80m2 and is aligned along the road. In the rear garden there is a shady terrace. Despite the ivy which completely covers the house, the render shows no sign of deterioration, proof of its durability. In the rear part of the land, there is a 100m2 shed built using the same method of composite light timber frame, but with no infill.

To know more about the construction technique, consult the article S&V of 1921 (in French) or a summary in your language.

The project website can be found here:  http://maisonfeuillette.compaillons.eu/ and deserves your consideration of support.

A Straw Bale Construction Wikibook

By Issue 62, Straw Bale Construction, Technical No Comments
By Duncan Lithgow
Straw Bale Building in Holland (Courtesy http://en.wikibooks.org/wiki/Straw_Bale_Construction)

Straw Bale Building in Holland (Courtesy http://en.wikibooks.org/wiki/Straw_Bale_Construction)

I love open content shared with everyone and improved by everyone. So back in 2006 after I was at the International Straw Bale Builders Conference here in Denmark I agreed to collect all the minutes and other documentation for the conference. I made this content into a website I hosted for  a while. But I was not satisfied with the reach of the content, it was only really people who went to the conference who new it existed. So I went to Wikipedia.org and discovered Wikibooks. As the name suggests, Wikibooks, is the the idea of Wikipedia applied to books. So I created a Wikibooks, with the unimaginative title ‘Straw Bale Construction’. The most developed part of the Wikibook is the ‘Technical Studies, Reports and Tests’ section which includes sections on Acoustics, Insulation, Fire Safety, Building Codes and Moisture. The most unusual part is perhaps the section ‘Pushing The Limit’ which looks at Straw Bale domes and arches (see the discussion page for a list of interesting links about that subject).
Then recently I got an email from Jeff at TLS announcing the relaunched website. So I wrote the text above and sent it to him. Quickly Jeff and I saw the potential of wrapping the TLS website around the wikibook. And with the wonders of modern website systems he had it working shortly afterwards. You can see the results at https://www.thelaststraw.org/the-journal/sbwiki/

So if you feel like taking a look, maybe even adding something, feel free. If you click on one of the ‘edit’ buttons you can get started. It’s a great place to add info on your national organization or some research you’ve heard about  – you don’t even need an account. All contributions are licensed for re-use, so if you find (or improve) a section worth publication on paper, let TLS know. And, yes, I keep an eye on all contributions. Write to me if you get stuck [email protected] and I’ll see if I can help.

New Feature!
The Last Straw is now hosting the content of this wikibook here, where it can also be edited and printed as if you are on the wikibooks site.  We encourage people to use this wiki as it appears to be the most comprehensive compilation to date on the web.  If you see something missing, 
incomplete or inaccurate, please participate and make this the most widely used wiki on natural building.
Duncan Lithgow works deep in the guts of Building Information Modeling on Northern Europe’s biggest hospital project, DNU http://www.dnu.rm.dk/.
 

Publication Review: The Straw Bale Alternative Solutions Resource by ASRI

By Book Reviews, Issue 62, Straw Bale Construction, Technical No Comments

SB_ASRThe Straw Bale Alternative Solutions Resource is a document prepared by the Alternative Solutions Resource Institute (ASRI) addressing, obviously, bale construction.  While the goal of ASRI is to “foster and facilitate the use of natural materials and systems in the construction of buildings…” this document is meant to focus specifically on bale construction and how these buildings can be permitted under the Alternative Solutions section of the British Columbia Building Code (BCBC).  For those of you familiar with alternative solutions, or alternative materials as described in the 2009 International Building Code (IBC), this document literally lays out the framework and arguments for the use of bale construction under the alternatives section of the BCBC.  While this is obviously geared toward the British Columbia provincial building code it has as much applicability in the context of other model codes around the world.  The complete and comprehensive nature of this document is a real lifeline for anyone requiring a permit in a jurisdiction with many questions about straw bale construction.

What makes this document most impressive is its coverage of all aspects of building science related to bale construction.  Moisture, plaster materials, fire, structural design, storage of bales, foundations, openings and box-beams are all covered in enough detail to lay a solid enough framework for anyone to permit a bale building.  The comprehensive nature of the document makes it required reading for all architects and engineers working on bale buildings.

While it covers pretty much every aspect that could come into question about bale buildings, it is geared for the seismically active maritime climate of British Columbia.  Expected rainfall in much of B.C. is heavy and they do not mince words when it comes to flashing windows, how far you should keep the bales above adjacent grade, and the role of roof overhangs.  While they do make sure that seismic design is addressed, they do not include any examples or give minimum requirements.  They do expect an engineer to be involved for the earthquake stuff.  One item to note that probably comes from being in a seismically active area is that all of their illustration show mesh being used in the plaster.  This conflicts with many purists view in parts of the world with low seismicity and moderate wind loads.

For the plaster junkies out there, it even has a section that will keep you interested.  It does a great job summarizing the basic concepts that we have come to terms with over the years and how a bale wall with plaster should perform.  As with the rest of the document, they do very well strongly discouraging the use of pure cement plaster due to the wet climate.  However, they do allow for cement-lime in appropriate ratios.

One important thing this document does really well is deal with terminology.  The basic premise first introduced in Bruce Kings book, Design of Straw Bale Buildings, is that the terms we use to categorize bale walls have been inaccurate and are widely misused.  According to this document the two types of bale walls are Structural and Non-Structural (much like all other wall types).  If you are going to use this document, you should get used to not using the terms  “load-bearing” and “post-and-beam” with the building officials.  Either the walls are intended to withstand vertical and lateral loads in excess of holding themselves up, or they are not.  How they are framed or stacked is of less relevance than how they are intended to perform, from a classification point of view.

Other notable items are clear statements such as the following:

  • “A minimum insulative value of R-28 may be used when calculating the thermal performance of a plastered straw bale wall using standard bales.”
  • “Conventional vapour barriers are not necessary or advisable.” (Polyethylene barriers are listed in a section titled Incompatible Materials, which also includes embedded rebar or metal and cement stuccos.)

Due to being in a wet region, one interesting inclusion is the following:

  • “In areas of high rainfall or high relative humidity, consideration should be given to making exterior walls “rainscreen-ready” in anticipation of the need for addition protection.”

In summary, the ASRI solution for bale construction is an impressive, well-written, comprehensive document that all professional practitioners of bale construction should have on their shelves.  While it does not go into detail as much as some books on the subject, it covers everything in a way that shows the authors did their research and left us with a worthy tool in our quiver.  The document is available from the ASRI Website for $25 to help offset costs and maintenance over time, as well as give ASRI a budget for their next projects, which, get this, includes the following:

  • cob
  • rammed earth
  • adobe block
  • light clay
  • earthen plasters and floor systems
  • thermal mass
  • on-site grey-water and black-water treatment
  • alternative healthy electrical technologies
  • passive and active solar integration, and
  • living roof installations

We should support them if they can do something similar for these other building materials and systems.

A Straw-bale Home in Idaho – TLS #55

By Bales, Design, Plaster, Roofs, Straw Bale Construction, Walls One Comment

This article originally appeared in TLS #55 and was the feature article in that issue.

house1by Wayne Bingham and Colleen Smith – Idaho, USA

Our interest in straw-bale construction grew out of our concern for energy efficiency. Our research into building energy efficiency grew into an awareness of sustainable building practices. An urge to build an energy-efficient home of materials that are sustainable grew as we explored these issues.

As we examined the site conditions for our home in Idaho, we found prevalent winds came from the southwest, passive solar orientation was due south, and views were predominantly southeast toward the Teton mountain range. The homestead to the west anchored the place visually and the rolling grass and grain fields to the north and east held their own hypnotic beauty.

We asked ourselves, “How do we place a building here and what would it look and feel like?”

From Small Strawbale by Bill Steen, Athena Swentzell Steen and Wayne J. Bingham. Published by Gibbs Smith

From Small Strawbale by Bill Steen, Athena Swentzell Steen and Wayne J. Bingham. Published by Gibbs Smith

We walked the site many times over several years, searching for the right place to build and the right kind of structure to build to respond to the soil, views, and
weather. When the irrefutable drive to build overwhelmed us, we went to the land and stayed for three days, walking, feeling, talking, and looking for the right place. We examined alternative ways of achieving solar gain while maintaining prominent views and avoiding challenging weather patterns.

The summer sun in our high mountain desert can be intense. The days can be hot, evenings cool down fast when the sun goes down, and the nights are cold. So a porch wrapped around straw-bale walls made sense to us. It can protect us from the sun, provide outdoor living space, and allow the straw bales and the internal thermal mass to moderate and maintain a relatively even temperature inside the house. The porch would also serve to protect the earthen-plastered bales from the weather.

We wanted the house to sit lightly on the land and allow the rolling surface of the earth to flow unimpeded past the house. We raised the porch surface only six inches above the adjacent ground around the entire perimeter to require only one step to grade.

We have visited and experienced several houses that deeply impressed us and we developed several drawings to reflect this approach. They were approximately square, had hip roofs and wrap-around porches. The deep porches were occupied with plants, chairs, tables, firewood, clotheslines, and other apparatus for living out-of-doors under cover.

After consideration of many schemes, we settled on one that is 34-ft. square, providing 1,156 gross sf and 961 net usable sf. Seventeen percent of the total area is in straw bales and the house is 83 percent efficient. It has a kitchen/living area, one bath, a master bedroom and guest room. There is a loft for the grandchildren.

Photos by Wayne J. Bingham

Photos by Wayne J. Bingham

Colleen had researched the area for organic straw bales that were 14-in. high x 18-in. wide. We found a farmer in Blackfoot, about 90 miles away, who had grown straw without herbicides or pesticides. Because the crop had matured and there was rain forecast, he cut and baled the straw. We had been working to have the house dried-in before taking delivery of the bales. We were able to place the bales under the newly finished roof before rains. Bale installation took only one week, notching and fitting under the roof and between columns and windows and doors.

Several friends called out of the blue and said that they heard that plastering was about to happen and could they come to help. Yes! Stan, John, Joe, Susan and I spent the weekend hand applying the beautiful chocolate colored earthen plaster mixed with long fibers of straw. We were at the end of summer and we wanted the plaster to dry before it could freeze, rendering earthen plasters no good. We were able to apply a rough coat on three walls over a three-day weekend. Brian and I finished the final wall in two days. The first weather coat had taken about one week. The building season ended and we left for the winter, planning to return the next spring.

diningWhen we returned in June 2003, we turned our attention to the final plastering on the main house. Sift clay, chop straw, mix clay to water, add straw and sand and apply to the rough coat completed last year. Check proportions, read the newly published book Natural Plasters, do tests and define how we want to do the work. Out of the research and study and questioning came a process we are very pleased with. We applied an infill coat of stiff plaster to the existing hand-applied rough coat using wood floats. We then brought the surface to within 1/4-in. of the /finish surface using a plaster that has more sand and less straw, sent through the chopper a second
time.

The final coat was applied with a steel trowel with curved corners, and polished with stainless steel Japanese trowels. It turned out quite nicely, with soft rounded corners and the bottom edge flared out to meet the metal drip edge.

We had read of clay “alis” paint. We read recipes in the two books and called the Steens asking for their advice. “Start with one part wheat paste glue, add two parts water, add clay until it covers your finger without showing a print.” We added one small scoop of burnt umber and about four cups of medium-sized mica flakes. We painted it on with 4-in. brushes, allowed it to become almost dry, and then polished with a damp (not wet) sponge.

Wow! What a difference it made. When plastering, the joints between one day’s work and another were visible, even though we tried diligently to feather it out. The alis unified the whole surface, and no joints were visible. It has a soft sheen from the mica, and it invites touch, as everyone who comes to the house exemplifies. Some have said it looks like leather. We think it looks like the earth around the house, but is refined by plastering and polishing. It looks like it belongs to its surroundings.

Building our house started out as a dream, a desire to do something sustainable, to build with one’s hands. Our project then became something physical, real, as we worked with the foundations, concrete, rebar, straw bales, earthen plaster, roofs, wiring, and all the rest.

In the summer of 2004, we installed a photovoltaic system to serve electrical needs of the house. We mounted the solar collectors on the garage porch. Batteries and inverter are in the garage with underground feeds to the house.

Well drilling estimates came in at $20,000, so we looked for another alternative. We built an 18,000-gallon underground cistern for a fraction of the cost that takes rainwater from the house and garage that passes through a filter before going to the tank. Before use in the house, it also goes through a charcoal and UV filter. It filled completely the first winter. With the exception of propane for heating and cooking, we are entirely off-the-grid. What a feeling of freedom!

Our home developed meaning for us beyond our wildest expectations. There has been a profound change in direction of our lives and satisfaction since we explored ways of becoming involved in sustainable building and focused on strawbale as a preferred method. Thirty-five years of life energy are focused on building our home. Feeling through our needs, responding to the site, and building the house day-by-day have been the most satisfying and meaningful experiences of our lives.

———————————————————————–

Wayne J. Bingham and Colleen F. Smith, a husband and wife team, have been involved since 1998 in straw-bale design and building. Their interest is an outgrowth of an exploration of energy efficiency and sustainable building techniques. In the mid-1990s, they attended several American Institute of Architect Green Building conferences where they began to understand the need for finding new ways to build without endangering the earth and its resources or future generations.  Seeking a direction of their own, they went on a natural building odyssey to the Southwest U.S. evaluating cob, adobe, rammed earth, earthship and straw-bale buildings, visiting or staying in each. They evaluated thermal performance, beauty, the feel, construction techniques and concluded that straw-bale building held the greatest possibility to satisfy their interest.

They attended The Canelo Project straw-bale and earthen plaster workshops and came away with a love affair with strawbale and earthen plaster that has not abated. Wayne immediately plastered their concrete block garden wall in their backyard with earthen plaster (see p 11 of this issue). They returned to the Steens in 1999 to spend a year involved with workshops, construction and collaboration with Bill and Athena on the development and production of Small Strawbale published in 2005 by Gibbs Smith Publishers.

Avid photographers and travelers, Wayne and Colleen have searched out and documented indigenous buildings in the United States, Greece, Great Britain and Italy and have developed a large library of images that were the start of the book. They took additional trips to explore and further record specific straw-bale buildings that now constitute a new book called Strawbale Plans.

In addition to Wayne’s working with owners and builders on straw-bale home designs and conducting workshops, Colleen and Wayne have put their experience into building this straw-bale home of their own in Teton Valley, Idaho. www.wjbingham.com

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)

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.

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