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Framing Bale Walls: How to

By Bales, Issue 63, Straw Bale Construction, Technical, Walls One Comment

By Andrew Morrison of strawbale.com

Image 1There are many different approaches to framing a straw bale house; however, there is one in particular that I have used on the vast majority of my projects over the years. It is a post and beam frame system with roots in conventional framing techniques. Because I came to straw bale construction many years ago as a general contractor practicing conventional construction, I brought some of that detailing over. I should preface this article by saying that there are right ways of framing and wrong ways of framing. The system I describe in this article lands in the “right way” column, but so do many other styles. As long as you are working with a structurally sound and safe system that brings you the best results possible for your style of building, then go for it.

Image 2One of the first details that often surprises people is the spacing of the posts in the system I use. I hear people talk about wanting to reduce the amount of notching in the bales by spreading their posts out as far as possible. I disagree with this approach and instead keep my posts relatively close together: no more than 6’ apart. One reason for this is that when the bales are stacked in between posts that are set far apart, there is no point of attachment for the bales other than the top and bottom of the wall. As such, the wall becomes weak as it is stacked higher. When posts are set closer together, the notches at each location provide a point of connection to the frame and make the wall much stronger both during construction and for the life of the structure.

Image 3One way I keep the posts close together is by incorporating them into the window and door frames. By using 4×4 posts as the king studs I end up with wider nailing surfaces on either side of the opening. This allows me to attach the finish trim, plaster channel and/or plaster lath, and welded wire mesh around every opening with positive attachment to the frame. These king studs serve two purposes by providing the nailing surface and by acting as part of the overall structural frame. Because windows and doors are placed in many locations around the home, and because I otherwise limit my post spacing to no more than 6’, I can minimize the wall beam size as a result. This minimal wall beam is important because the bigger the beam, the more expensive it will be. Further, larger beams are made from larger trees (unless an engineered beam is used) and I want to reduce the size of the trees I am using in my projects for environmental reasons.

Okay, let’s take a look at how the system works and why it can save time and money in your building process. I’ll simply lay out the process so you can see, step-by-step, how it comes together.

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THE SITUPS*: Super Insulated Tilt-Up Panel System.

By Bales, Issue 63, Prefabricated Panels, Straw Bale Construction, Uncategorized, Walls One Comment

By Huff ‘n’ Puff Constructions

Editors Note: We plan to have a comprehensive article covering as many of the tilt-up straw panel systems on the global market as we can in Issue #64 due out in July.  Please also note that the images associated with the thumbnails on this page are of large size.  We wanted to keep them original size to allow you to see details clearly.

INTRODUCTION
Recent times have brought an increasing wave of environmental and energy efficiency awareness in the building industry throughout Australia.  This increased awareness of the effect of logging on our forests, lakes, and streams, as well as heightened concern for the energy cost and efficiency of our buildings and ever-increasing costs of construction materials is bringing tremendous pressure for change to the Australian building industry.

A primary focus of this change is the development of alternative forms of construction for single and multi-family housing as well as commercial and industrial buildings.  With a tradition that dates back almost 200 years, the Australian building industry has utilized timber extensively for use in wood frame construction, concentration on wood framing timber as the principal raw material for the structural shell of the majority of our housing and much of our light commercial structures has tremendously diminished our hard wood and softwood forest resources in Australia.

The cost of framing timber has more than doubled in the past five years. The price of timber is projected to continue to rise over the course of the next decade with additional concerns over the quality and availability of that timber.  The price and in some areas the availability of energy has added a new and important factor in most building projects.  With these facts in mind, the building industry, known for its rigidity and resistance to change, will have to look at replacement materials for framing timber in home and commercial construction.

THE SITUPS*
We are in the process of developing and bringing to the market place a unique, and ecologically sound, structural insulated panel building system.  These panels will be able to be put into place by two people.  This structural panel system provides a cost-effective, building system that is based on an environmentally responsible manufacturing process.

Huff ‘n’ Puff Constructions are manufacturing a structural super insulated panel that uses as its core material waste agricultural cereal straw from wheat and other cereals commonly grown in Australia.

SITUP Prototype

SITUP Prototype From TLS #24

With the recent high rise in energy costs and energy availability this product’s value to the builder and his client is a product that is more important now than ever before.  THE SITUPS* is highly competitive to conventional building methods.  With the reduced construction time, energy savings, non-toxic nature of the product, and strength and durability of the product indicate we have a building system whose time has come.

HISTORY
It was on the banks of the Murrumbidgee River at Hay that we made our first SITUP.  This event was first published in The Last Straw many moons ago now.  It involved a BIG chain saw and a jumbo straw bale 2.4 m x 1.2 m x 1.2 m (8’x4’x4’).  We made three panels out of the one bale and had a lot of waste with the “method” we used at that time.  Back to the drawing board…  [Huff ‘n’ Puff shared this technique in TLS #24, Winter of 1998]

01 Testing 2

Testing

In between building straw bale houses and wineries we kept on refining the process over the past 8 years.  Eventually we got an order to make 60 x 2.4 x 1.2 x 150 mm panels for a straw bale house that we were building in Kangaroo Valley, near Sydney.  These panels were to be used for the internal walls and are non-load bearing. 

We had these internal panels tested at the University of Western Sydney.  Our tests were to establish their load bearing and wind loading capacity.  They did not pass muster for load bearing but showed us their potential.  However the size of 150 mm wide proved to be very hard to manufacture and will need a lot of refining in the 03 Kangaroo Valley 1 (1)process to make them a worthwhile proposition.

FIRST LOAD BEARING PROTOYPES
After many experiments and research we have chosen a method that we feel has the potential to change the way we build with straw bales now and into the future.  We also realise that several straw panel systems are now on the market in parts of Europe and Canada.  Our opinion is that more is good and will only lead to the acceptance of building a house, flats and even high rise units and many other types of building by adopting straw as the medium in tilt-up wall technology.

07 Wagga Wagga 2 (3)

Near Wagga Wagga

We have now completed two SITUP buildings in New South Wales.  One close to home in a suburb of Wagga Wagga, and the other on a farm near Yass, which is close to Canberra.  We are now filling an order for a three-pavilion SITUPS home in the Hunter Valley of New South Wales.

11 Yass 1 (4)

Near Yass

The SITUPS are currently 2.450 to 3.000 metres high and come in various widths from 600 mm to 1.2 metres.  We can also make them between 350 mm and 450 mm wide.  The cladding can be a variety of material from renders to weatherboard, corrugated iron and many other forms of external sheeting.  Internally they can also be clad in render or Gyprock and various types of lining boards.

We are also developing a portable SITUPS factory to make these on a building site.

SUMMARY
The SITUPS will greatly reduce carbon emissions from new buildings through savings during manufacture and the operation of the building.  We already know this, having built many straw bale buildings since 1998 and together with 145 straw bale building workshops now completed.

Hunter Valley

Hunter Valley

Our goal is twofold; first, to reduce the carbon impact of modern buildings with the SITUPS and; second, to be able to utilize a waste product of our wheat and rice cereal growing in Australia where rice straw alone is burnt at an alarming rate.  Some one million tonnes goes up in smoke (particulates and carbon) every year.  Enough straw to build, say, 44,000 three-bedroom SITUPS homes on an annual basis and that is only from the rice grown in one area of Australia.

All the other benefits that come with straw bale homes that we have know of and practiced over the past 17 years apply equally to the SITUPS.  The main difference to conventional building with straw bales is that the SITUPS are uniform pre-compressed at time of manufacture and hence are very fast to build with, saving time and money.

* The SITUPS is a registered trademark of Huff ‘n’ Puff Constructions

John Glassford and Susan Wingate-Pearse, The Straw Wolf and My Little Wolverine
Huff ‘n’ Puff Constructions
“Jack’s Flat”
22-24 Moore Street
GANMAIN N.S.W. 2702.
AUSTRALIA
61 2 6927 6027 Work
0412 11 61 57 Mobile
[email protected]
http://www.glassford.com.au

Wrap-Up of the Ontario Natural Building Coalition Annual Natural Building Conference

By Community, Issue 63, Straw Bale Construction No Comments

By Frank Tettemer, ONBC Director

Chris Magwood

Chris Magwood, speaking about setting goals and design priorities

This definitely was the most fun to be had all winter.

Timing is everything, and this year’s gathering of the clan at Camp Kawartha, near Lakefield Ontario, warmed my heart during one of the coldest of Canadian winters. With temperatures outside the straw bale conference room dipping to -24C (-11F) at night, the crackling fire in the wood stove provided a popular place to gather around over the weekend.

Tina Therrien’s welcome and opening remarks on Saturday morning lit the flame of curiosity and instilled the warm comradeship that nicely permeated the weekend conference. Her dedication to forming the Ontario Straw Bale Building Coalition 15 years ago, and her continuance as Chairperson has been instrumental in supporting this organization’s transformation into what it is today; the Ontario Natural Building Coalition. www.naturalbuildingcoalition.ca

Jacob Deva Racusin spoke of many things around building impact, social justice, and creativity. Lessons learned were all about making straw bale walls using additional layers and materials. The synergy of plaster, straw, cellulose, rain screens, and cladding can easily place natural materials into the Passivehaus world of warmth.

Jacob Deva Racusin

Jacob Deva Racusin on natural building impacts, social justice, and creativity

Chris Magwood’s presentation reached out to owner-builders, professionals, and designers, about the importance of setting goals and priorities, well before the excavator arrives on site. Emphasizing that everyone’s needs are different, and establishing priorities for each individual is the first step in good design. And when it’s time to compare different materials and building components, his new book, “Making Better Buildings”, covers everything vital and appropriate.

David Eisenberg’s warm voice and brilliant experiences always open my heart. While transplanting Kathleen O’Brien’s Emerge Leadership project to the forests and lakes of Ontario, he found fertile soil, within this group of 80 aware and alert natural builders.  Though it must have been a challenge for him, to travel the distance with a temperature difference of +80F to -11F, ‘Desert Dave’ seemed undaunted, as he patiently germinated the seeds for emerging leaders, to carry on the work of building not just net-zero housing, but to develop ways in which every new building is restorative and adds benefits to the natural environment.

Dawn Marie Smith traveled from Victoria, BC to show us how to use alternative methods to achieve code acceptance and obtain that elusive building permit. Reaching for the carrot of sustainable building is not always easy, and the ASRi and their publication, the Alternative Solutions Resource Initiatives’ Straw Bale Alternative Solutions Resource (ASR) manual, has made the work of digging these carrots much more straight forward. I loved how her experiences with Emerge Leadership helped to add sprinkles of additional insights during David Eisenbergs’ presentation.

Relaxing after dinner on Saturday, we were treated to our own 5×5 slideshow  – five photos from a couple dozen contributors – who each had five minutes to talk about their photos. Hilarious and inspiring, the show was a fun warm-up to the evening, that included libations from a selection of organic wines and craft brewed beers from the Bale Heart Bar, that livened up our senses for socializing, while singer-songwriter Rick Fines strummed and sang, caressing the spirit of inspiration in us all.

Did I mention how well we were treated and fed by the Camp Kawartha cooks?  They really knew how to accommodate the evolved diets of our participants, with delicious meals and healthy snacks.

Thanks to all, for your spirited participation, in making this year one of the finest conferences ever.

References:

Tina Therrien – http://naturalbuildingcoalition.ca/  &  http://www.strawhomes.ca/

Jacob Deva Racusin – http://www.chelseagreen.com/bookstore/item/the_natural_building_companion:paperback%20+%20dvd & newframeworks.com/

Chris Magwood – https://www.newsociety.com/Books/M/Making-Better-Buildings  &  http://www.chrismagwood.ca/

David Eisenberg – http://www.emergeleadership.net/  &  http://www.dcat.net/index.php

Dawn Marie Smith – http://www.asri.ca/

Rick Fines – http://rickfines.ca/

Camp Kawartha – http://www.campkawartha.ca/ http://rickfines.ca/

Community Rebuilds – Path to Zero Waste

By Bales, Community, Issue 63 One Comment

By Stuart Jeffrey Hart

SJH_3556

Courtesy of Stuart Jeffrey Hart

Community Rebuilds is a nonprofit organization that builds straw bale homes for low-income families in Moab, Utah.  The homes are built by volunteers who exchange their time for an education in natural building and sustainability. Our student intern volunteers commit to the entire 4 month build, participating in the foundation pour all the way to ‘key in the door.’ Our program is committed to replacing dilapidated, energy wasteful trailers, for highly efficient homes that use a fraction of the energy to heat and cool.

Community Rebuilds was been awarded this year’s “Innovative Path to Zero Waste Award” by the Utah Recycling Alliance. Here is how we achieved it.

To reduce the waste we produce on the build site, we follow the ‘Reduce, Re-use, Recycle’ principle.

Reduce – Our design choices help us reduce the amount of building materials that we use. When ordering roofing metal for example, we use Google Sketch-up, a computer-modeling program, to lay out the exact cuts needed. It shows us where the off-cut from one piece can be used elsewhere. This allows us to order the precise lengths of metal needed, meaning less materials are ordered and we produce the minimum waste possible. All lumber is ordered at lengths specific to the building needs. We order lumber lengths as close to the actual length needed to reduce the amount of material left. The conventional approach is to order only 16 ft lengths, then cut everything from those. The remaining pieces are often too short to be used and are discarded as waste.

Pallet Warriors (courtesy of Douglas Nichols)

Pallet Warriors
Courtesy of Douglas Nichols

A major design choice is for our houses to incorporate natural materials that are compostable. We choose to build the walls of our homes with straw bales, an agricultural industry waste product that would otherwise be burned. Extra bales and waste straw are composted. The homes we build have earthen floors and the walls and ceilings are plastered with earthen plaster. We use a combination of locally sourced sand, clay and straw for all of these applications. Plaster mix that is dropped during plastering or left over at the end is either re-hydrated and used again, or simply spread in the garden to become the soil.

Reuse – We incorporate used and repurposed building materials into our homes to reduce the cost of the homes and to reduce the amount of new building materials required. We construct non-load bearing interior walls with pallet wood salvaged from the local waste stream and earthen plasters. In addition, we reuse functional lumber, tiles, doors, windows, interior lighting and plumbing fixtures, sinks and toilets.

During construction we reuse our waste as much as possible and we try to incorporate other people’s waste material when possible. When sheeting the internal walls of our homes, we use drywall off-cuts from other build sites. Conventional construction crews will not use drywall scraps. Scraps will usually be the end of a 12′ x 4′ drywall sheet. We flip all the 4′ pieces horizontally and use them to span our 2′ on-centre framing.  In our homes we piece together a total of 960 sq ft of ‘waste’ drywall. We mesh tape the extra seams and clay slip the gaps, and then our earthen plaster hides all.  By collecting the salvageable scraps and using them in our homes we reduce the amount of waste destined for the landfill and save purchasing new materials.

When we are building with other conventional materials excess material and remnants are incorporated in the home as much possible. We use rigid foam insulation sheets to insulate our foundation and underneath the floor. Scrap from this process is saved and inserted into the roof cavity before we blow in cellulose. Some burnable wood scraps are collected together and used by the volunteers in their wood burning cob oven and communal fire pit. The rest is donated to a local family who use it to heat their house throughout the winter. We donated four cubic yards of burnable wood scraps from our most recent build.

We choose to use as little wood that contains glues as possible. This means that more of the wood scraps are burnable. It also reduces the amount of potentially harmful chemicals in our homes. To replace OSB sheeting on the roof, we use rough sawn 1×10 wood for the same price. We have replaced LVL beams with rough sawn 4×12’s.  Both of these come from the Colorado Rockies where pine beetles have devastated huge areas of pine trees leaving them standing dead.

Reused MaterialsRecycle- We challenge ourselves to limiting our waste production to one domestic garbage bin (0.5 cubic yards) weekly. Our waste consists mainly of non-recyclable packaging and cumulates to an average of 8 cubic yards per build.  By comparison, we estimate that local private contractors will dump approximately 30 cubic yards of waste during a similar sized build. 
To accomplish our low waste goals, we begin each new home build by creating pallet-recycling bins on our construction sites. Metal, plastic, cardboard and wood scraps are stored in them. When we need a small piece of lathe to patch a crack, some wood for blocking or cardboard to protect our floor a quick check of the recycling bins can save cutting a new piece. Once the build is over anything that hasn’t been used is recycled. At the end of our previous build we recycled one cubic yard of scrap metal and one cubic yard of cardboard.

Our goal is to create a quality affordable product with minimal waste and environmental impact. In doing so, we educate the next generation of builders how to move towards zero waste. Our students learn how the current building methods are wasteful and inefficient and how, using just a small amount of planning, we can change the home construction paradigm for the better. We are building homes in a smarter, more sustainable way. Our homes’ energy performance, thoughtful construction methods and quality stand as an example for our volunteers, the community and the construction industry as a whole.

Jeffrey was an apprentice and natural building instructor with Community Rebuilds from 2012 – 2013. 
He is now heading home to his native England to build small, affordable, straw bale homes using the Community Rebuilds volunteer/educate model.  He can be found at www.jeffreythenaturalbuilder.com.

 

Book Review: Making Better Buildings

By Book Reviews, Issue 62 No Comments

Reviewed by Jeff Ruppert

Image-front-cover_coverbookpageMaking Better Buildings: A Comparative Guide to Sustainable Construction for Homeowners and Contractors by Chris Magwood will be released this Spring and promises to be one of the most valuable tools for the designer and builder who wants to understand how their choices of systems rank in terms of environmental impact, cost and acceptability.  No other compilation gives such an in-depth review of the most widely used natural building techniques.  Not only will you find the tried and true methods of straw bale and rammed earth construction, you will find alternatives you never knew existed.

Being a guide, this is not a how-to manual.  It does not have pictures showing how to build alternatives to concrete foundations, for example.  What this book does is ensures you are not missing something, and if you are you will easily find it and be able to compare it quickly to what you think is the best choice.  The information on each system is objective and easily referenced.  What is so impressive about this book is the list of systems it covers:

  • Foundations
  • Walls and Insulation
  • Floor and roof structure
  • Sheathing and cladding materials
  • Roof sheathing
  • Flooring
  • Surface finishing materials
  • Windows
  • Mechanical systems
  • Water systems
  • Wastewater systems
  • Heating and cooling systems
  • Electrical generation

As a designer of natural buildings I found the tables used for comparison very easy to glance through.  I was able to discern the most valuable information quickly once I became familiar with the format.  Comparing choices is easy and finding the characteristics that may keep one system or another from fitting into a project simple.  The format forces you to think about each system using the same set of parameters, such as code acceptance, embodied energy, waste generated, costs, durability, etc.

But let’s not mince words when talking about green building.  This book is clear – the current mainstream methods of making buildings sucks from an environmental point of view and no matter how certified they are, they just aren’t that green.  The systems reviewed in this book address the most fundamental issues facing our society and the construction trades.  Systems such as steel and concrete construction are not included due to the simple fact that both materials cause huge harm to our environment.  There is no need to waste paper (or bandwidth) on the higher end of impact and societal costs when you are focusing on real solutions.  If you are reading this book it means you are serious about considering real alternatives in this day and age of high impact buildings and “greenwashing.”

Chris Magwood continues to bring us fresh ideas and perspectives with this publication.  We recommend it not only to the professional designer and builder, but also to owners who are serious about making better choices on their next project.

Making Better Buildings will be available in March for $39.95 USD and CAD from New Society Publishers.  It is approximately 460 pages and will be available in both paperback and as an eBook.  

Paperback ISBN: 978-0-86571-706-0; eISBN: 978-1-55092-515-9

Disclaimer: Chris Magwood has appeared as guest editor in past issues and submits articles regularly to The Last Straw.

 

A Gentler Path to Building Permit Approvals

By Codes and Permits, Issue 62, Straw Bale Construction No Comments

By Andrew Morrison

codes1There has been so much talk over the years around the “straw bale building table” about building codes and how they get in the way of our ability to build with natural materials. I have heard people talk about how building officials have ruined their dreams time and again, and stories about building officials requiring so many “over the top” details in a home that building it became impossible.  You can imagine, therefore, that I tend to shock people when I tell them that I actually like building officials and that I prefer job sites that have an inspection process over those where no building officials visit the site. Let me explain.

If you have ever been to a job site where no building inspections take place and no plan review is required, you may have seen what I have seen: a house that is built below code with several omissions and/or mistakes which put the occupants at risk. For example, deciding to save a little money by not installing collar-ties between your rafters could lead to the roof’s collapse and your death or injury. That’s certainly not worth the money saved. Just because you are not required to build to code doesn’t mean you shouldn’t. A lot of thought has gone in to developing the building codes we use both here in the States and abroad. You may find that some are overkill and some are unnecessary based on the scope of your project; however, I strongly recommend that you adopt as many of the code provisions as you can in order to provide a safe home for you and your family.

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Healthy Living, Healthy Building (Building an EcoNest)

By Bales, Design, Issue 62, Straw-Clay, Walls No Comments

By Elaine Brett

Finished WallsTwelve years ago I had never even heard of building with straw.  I lived in a four-bedroom colonial house in a subdivision in Maryland.  The conventional American Dream – good job, big house, nice cars, the monthly lawn service, the health club membership, 24/7 access to shopping …

Then on my 49th birthday came the American nightmare.  A wake up call from Mother Nature.  Sometimes she needs to smack you hard to get her attention.  My wake up was a cancer diagnosis that sent me spinning into a quest of asking questions and trying to understand “how could this happen to me?”

One path of my quest (probably driven by my background as a chemist) sent me questioning the chemicals in my environment: the food I was eating, the air I was breathing, the water I was drinking, the lifestyle I was living, the buildings in which I was residing and working.  The answers took me beyond the overt pollution of urban air and water to the hidden nooks of micro pollutants in synthetic materials, chemical food processes and endocrine disrupters in simple everyday products.

The quest also took me on another path.  I began looking for a place to live clean and chemical free, or at least as clean as is possible.  And that’s how I came to a small town in the North Fork Valley (www.northforkvalley.net) in Western Colorado.

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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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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

Welcome!

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Important!
We have identified and fixed a glitch in our subscription system that created problems for non-U.S. folks to subscribe.  If you have had problems in the past, please try again and let us know if you continue to have problems.  Thanks for the support!

The Last Straw has undergone a transition over the past year and we’re having a revival of our own.

Russian_BalerWe are now part of the Colorado Straw Bale Association (COSBA).

TLS has come a long way since the days of Out on Bale (un)Ltd where it was created back in 1993.  It is with great honor that we continue the TLS tradition and have the opportunity to upgrade it to reflect the times in which we live.

While much has changed behind the scenes our mission remains the same, which “…is to inform and inspire people to build more consciously and with foresight toward future generations.

With the digital age well upon us we are offering our subscriptions a little differently and hope to bring you even more interactivity with the publication.  By becoming an annual subscriber you will receive both print and pdf versions of each issue.  We want you to be able to access your documents from wherever you are, which means we are considering implementing an online reader for your convenience.

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