The steps from start to structure...

by Matt Robinson – Arizona, USA

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

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

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

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

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

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

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

by Kaki Hunter and Doni Kiffmeyer – Utah, USA

We live in the heart of the great Southwestern United States, surrounded by examples of one-thousand-year-old ruins left behind by the ancient civilizations of the Anasazi, Hohokam, Pueblo and many others. It was these original natural builders that inspired us to consider building with earth as a way to create beautiful, low-impact, energy-efficient housing that has endured the test of time to this day.

We started by teaching ourselves how to make adobe bricks, the most common earthbuilding technique native to the U.S. Making adobe bricks turned out to be a lengthy process that involved mixing the mud, pouring it into forms, lifting the forms, and then turning the blocks over the next several days to facilitate even curing. The blocks then had to be stacked and protected until ready for use. Manufacturing the adobes required a considerable amount of space for both the pouring process, as well as for storage of the dirt needed to make them, and then the storage of the adobe bricks themselves until they were ready for building. We live right in the heart of a small town, which made this process a little tight.

The dirt for adobe block and most other forms of earthen architecture require a specific ratio of clay to sand, ideally about 25 to 30 percent clay to 75 to 70 percent well-graded sand. In some cases, a stabilizing agent may be added to an earthen soil to increase its compressive strength and make it resistant to the affects of water. Some earth building techniques like cob require copious amounts of straw fiber added to the mix. In most cases, adobe brick also benefits from the addition of straw or some other kind of natural fiber.

Honey House

After our initial foray into homemade adobes, we read about the work of international award-winning architect Nader Khalili. Nader is an Iranian-born architect who abandoned a successful career designing skyscrapers to follow his heart, which led him to create an innovative sandbag/superadobe/earthbag architecture as a means of providing low-tech, enduring affordable housing. Inspired by the ingenious monolithic adobe buildings of his homeland of Iran, Nader conceived the idea of building domed and vaulted structures with…bags of earth. We took a one-day workshop with Nader and we were hooked! We returned home excited to build our first earthbag-wall project, a privacy wall opposite the busy baseball field across from our house. However, our interest quickly zeroed in on the building process itself. We began innovating tools, tricks, and techniques that we felt made the building process more enjoyable and the results cleaner and predictably solid. We coined the acronym FQSS which stands for Fun, Quick, Simple and Solid. The process has to be Fun, which makes the work go Quickly as long as the procedure is kept Simple and the end results are Solid. Hence the FQSS stamp of approval became our dirtbag golden guideline.

Earthbags (as we were soon to discover) had the advantage of being able to use a wider range of soil types than traditional earth building techniques – “Wow, this dirt’s just got five percent clay and it still works!” We have been able to adapt soils for use in earthbags that have ranged from zero clay to 50 percent clay content. No type of fiber was needed within the soil. Since the bag acts as a textile container for the earth, the woven fibers do the job of stabilizing the soil in place so the soil can have a lesser quality binding strength than required for most other types of earthen construction. When necessary, even dry sand can be used as fill, as could be the case in providing emergency relief shelter. The Earthbag System is a contemporary form of earthen construction that uses modern woven polypropylene feedbags (usually misprints) or long tubes as a flexible textile container (or what we call a flexible form) preferably filled with dampened soil. The bags or tubes are filled in place on the wall being built so there is no heavy lifting. After a whole row is laid, the bags are compacted from above with hand tampers. The compacted earth later cures to a cement-like hardness. Two strands of four-point barbed wire are laid in between every row that act as a “Velcro” hook-and-latch mortar, cinching the bags together while providing continuous built-in tensile strength. Tensile strength inhibits the walls from being pulled apart during stressful conditions like earthquakes, floods, hurricanes, and load-bearing and lateral forces. The combined strength of the four-point barbed wire sandwiched in between the woven textile fabric of every row of earthbags adds a significant degree of tensile resilience that is lacking in most traditional forms of earthen architecture.

The soil we selected for our initial earthbag building projects was delivered from our local gravel yard at 80 cents per ton. That was ten years ago. Today we pay about $1.80 per ton. Reject sand or crusher fines are common names for the clay fines that are the byproduct from the manufacture of washed sand and gravel produced at most developed gravel yards. Often, this reject material has sufficient clay-to-sand ratio to produce strong compacted earthen blocks. However, over the years, we have had considerable success with using almost any type of soil available on site by paying particular attention to adjusting the moisture-to-soil ratio that produces the optimal strength block.

Building the earthbags around temporary rigid box and arch forms creates door and window openings. After compaction of the keystone bags, the forms are then removed. Wood-strip anchors are installed during the wall-building process, providing an attachment for bolting on doorjambs, cabinetry or wood-frame intersecting walls, electrical outlets and plumbing systems.

Wall plastering options range from thick natural earthen plaster applied directly over the surface of the bags (yes, it sticks!) or, for additional protection, lime plaster can be applied over an earthen plaster. Cement/lime based plasters perform well when the earthbags are filled with a stable, well-draining sandy soil and applied over stucco mesh (chicken wire). Plasters can be applied by hand or sprayed on with a pressurized plaster sprayer for a unique contoured effect that accents the shape of the bags or tubes.

Earthbag Architecture can be designed to suit a wide variety of climates. Since the woven polypropylene bags are virtually rot proof, earthbags are an excellent choice for underground structures: root cellars, storm shelters, bermed homes and greenhouses. In climates where wood is scarce, whole houses can be built exclusively with earthbags including the foundation and roof, as is the case for corbelled earthbag domes. Earthbags also combine well with other natural building materials that can be combined together to create hybrid structures. Straw bales can be interlocked with earthbags to build sturdy arch entryways or to add thermal mass to the interior wall of an attached sunroom. Or we may choose to use earthbags for the sunken first level of a structure and then switch to strawbale, post-andbeam, cob or adobe brick for the rest of the wall above grade to make use of an available resource or add aesthetic variety.

The advantage of combining two alternative natural building mediums: load-bearing earthbag walls provide mega-thermal mass, while an exterior straw-bale wrap provides mega-insulation.

Insulation strategies for earthbag walls offer a variety of options. Narrow tubes provide a sturdy load-bearing wall with plenty of thermal mass, while straw bales secured to the exterior of the wall provide ample insulation. Now, we have mega mass coupled with mega insulation to provide the best use of both of these materials in one building. Another way to add interior mass is to build our interior walls with earthbags and our exterior walls with straw bales alone. Another approach we have experimented with is mixing a percentage of 3/4-inch pumice to a quality rammed earth soil that captures air spaces within the earthbag itself. A 50/50 mix of suitable earth and pumice make the bags one third lighter than their normal all dirt weight yet still makes a nice hard compacted earthbag.

Building codes

The advantage of combining two alternative natural building mediums: load-bearing earthbag walls provide mega-thermal mass, while an exterior straw-bale wrap
provides mega-insulation.

The earthbag building system has been extensively tested by Nader Khalili in conjunction with the ICBO (International Conference of Building Inspectors) and the Hesperia Building Department in Hesperia, California, at the California Institute of Earth Art and Architecture for earthquake resilience, loadbearing, and shear strength stability, all of which were proven to far exceed conventional code standard acceptance. (See Building Standards issue Sandbag/Superadobe/ Superblock Sept-Oct 1998 for a full article on the merits of Earthbag structural nitty-gritty).

Resources

Sources for bags and tubes can be found on the Internet under woven polypropylene feed bags. Our favorite U.S. supplier for both pillow-pack and gusseted misprint bags is www.innpack.com, toll-free 800.622.3695 in Tennessee. Typical prices for 50-lb misprints are approximately $.17 each (USD), and 100-lb bags are $.25 each (USD). Both come in bales of 1,000 bags. Smaller quantities for bags and tubes are available from a Kansas City, Missouri, source www.centralbagcompany.com 816.471.0388. Ask for Chris Klimek for prices and selection. Also try 800.521.1414 www.fultonpacific.com.

For step-by-step nitpicking details about building with earthbags, check out our book Earthbag Building, the Tools Tricks and Techniques by Kaki Hunter and Donald Kiffmeyer, New Society Publishers, 2004. Or call us at 435.259.8378, or visit our web site www.okokok.org.

Donald Kiffmeyer and Kaki Hunter have been involved in alternative construction since 1993, specializing in affordable, low impact and natural building methods. Inspired by the work of visionary architect Nader Khalili, the grandfather of Sandbag/ Superadobe/Earthbag architecture, they wrote a screenplay entitled “Honey’s House,” a film about truth, justice and affordable housing. From these innocent beginnings, they were launched into the alternative building movement where they were encouraged to share their combined innovations to establish the Flexible Form Rammed Earth technique. Together they co-authored the book Earthbag Building, the Tools, Tricks and Techniques by New Society Publishers. They live in Moab, Utah, where they continue to focus on the research and development of fun, quick, simple and solid natural and alternative building techniques that are inspired by this fabulous planet.

Thank you for your patience and understanding as we move forward.

The Last Straw Blog

Slope pan flashing to outside.

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

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

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

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

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

What is the ratio of your mix? Let your sand tell you!

This article is original content and has not appeared in The Last Straw.

St. Astier Natural Limes, a producer of hydraulic lime products from France, is offering a set of DVD videos called The Master Stroke DVD Tutorial Series.  The Master Stroke is a 4-disc series beginning with lime mortars.  Other discs cover plastering and rendering with lime, and building and pointing with lime.  In this article we will review the first in the series, Making Lime Mortars.

The content of the DVD is laid out very clearly and is easy to follow.  The quality of the video is very polished. The main purpose of the DVD is to show the construction worker how to create a consistent, high-quality mortar or render.  Tips include how to properly keep your sand dry, how to measure each bucket of sand, etc.  But there was one piece of information that really make this video important.  Nearly half of the video is dedicated to the concept of the sand void ratio and how it affects your mix.

Have you ever wondered where the ratios we use for our mixes come from?  This video explains how they are derived.  Without going into too much detail, the ratio of sand to lime is determined by finding the void ratio of your sand.  Once you know how much air is between the grains of sand you can find the volume of binder.  If you use too much binder, the sand particles will be far apart, separated by water and lime.  If you use too little lime you are not filling all the voids with lime and you will have pockets of air and water.  The perfect ratio is one that fills all the voids and leaves little room for air or water.  Once you know this ratio, based on your sand, you can then adjust the ratio to achieve your desired results.  Don’t think you can just figure this out on your own through this article.  There is a proper way to do this, and each step is clearly defined in the video.

To know the proper ratio of sand to lime (or any other binder – clay, cement, gypsum, etc) is like an enlightenment for most of us.  Have you ever wondered why the code says 4:1:3/4 (sand:cement:lime), or why your friends used 1:2:9 (cement:lime:sand)?  Now you don’t have to guess.  Watch this video and learn how to properly measure the void ratio of your sand and the ratio of sand to binder.  It will become apparent that the mix your friends are using on their project has little bearing on your mix.

Mortars, renders and plasters all folow the same ratio and mixing concepts.

Learning how to derive the ratio of sand to binder is obviously very valuable.  The rest of the video walks you through the measuring and mixing process, showing how a professional would prepare his or her mortar.  After being a sub-contractor and mixing thousands of batches of plaster, this video would have been great as a tool for estimating.  In my mind it creates a baseline for high-quality that a builder can use to determine costs.

In summary, I would say buy this video!  It can be purchased at the link above for $39.  From novice to professional, you will find value.  Good luck.

This review is intended to be objective.  No compensation of any form has been accepted in connection with this article.

by 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

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

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.

When 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

by Rene Kilian – Denmark

Save money on your black and grey water while protecting the environment!

Reeds and iris clean the wastewater in the planted filter.

All properties without sewage facilities in rural areas of Europe must meet minimum standards for wastewater treatment. It can be expensive joining on to the main sewage lines. A planted filter’ – a modern kind of reed-bed system with vertical waterflow – has low operating costs and is an inexpensive alternative.

Approximately 30 of these filters have been built in Denmark. The systems are planted with wetland plants, and occupy around 16m² per dwelling.

The system complies with the latest Danish standards, which are stricter than the European standard.

Along with this, environmental impact is reduced and the homeowner can save money on sewage connection and payments.  The investment can be paid for through savings in less than five years, when compared to a standard sewage connection. Here is an example.

Reuse of treated wastewater
Søren Raffnsøe built his own straw-bale house, went about it in a way that was as environmentally and economically friendly as possible. The way that water comes in and out of the house has
been considered in a holistic manner, and is the first of its kind in Denmark.

The house has its own planted filter to treat wastewater. The system is only 8m2 because the house has a composting toilet.

The planted filter is a biological-cleaning system. The system, designed by René Kilian, is an effective alternative to a sewage connection. The system can even be integrated into a garden where it could resemble a garden bed growing with thatching reeds, iris and bullrushes.

Figure 1. A recycling system with the planted filter where water is reused in the washing machine and garden. 1. Sedimentation Sedimentation tank for grey wastewater only. The source of the water may vary depending on local codes or regulations but might include water from bath, washing machine and kitchen. 2. Pump well with a level controlled pump. 3. Reed bed system or constructed wetland. 4. Tank for treated wastewater and treated rainwater. 5. “Green” pipe for reuse water to washing machine and garden. 6. Water vitalizer in drinking water pipe. 7. Fine filter for treatment of rainwater. 8. Untreated rainwater toward sand catcher and infiltration unit. 9. “Black”’wastewater from toilet to compost container. 10. Urine from toilet to urine container Design by Kilian Water Ltd., Denmark

The recycled water becomes so clean that you can reuse it to flush the toilet, wash clothes and water the garden. As compost toilets don’t use water, Søren uses the water only in his washing machine and garden. See Figure 1.

Along with this, he saves 50 percent in his usage of drinking-quality water. To collect the excess recycled water, he has made a little pond in the garden, where there is an extra cleaning process that created a habitat for plants and animals. The drinking water itself is also special. He has installed a ’vitalizer’ in his drinking water pipes. This revitalizes the water so it attains the same quality as spring water.

Payback in less than five years

A planted filter of 16m2 suitable for a normal household, will cost around 60,000 Danish kroner/$11,083.80 USD. Connection to public sewage costs one household around 40,000 kroner/$7,389.21 USD. The investment can be paid back in less than five years, as you can save on annual wastewater bill payments. Ongoing costs for a planted filter are 0 kroner /m3; there is just a government tax of 1.60 kroner /m3. Costs for sewage are approximately 35 kroner /m3. This means a dífference of nearly 33.50 kroner / m3. With an average consumption of 170m3 per year, a household would save around 5,700 kroner/$1,052.96 USD per year, or 140,000 kroner/$25,862.20 USD after 25 years.

The planted filter at 8m2 in front of the newly built straw-bale house.

If you chose a reuse system in addition to this, and saved 50 percent on water consumption, you save 7,000 kroner/$1,293.11 USD per year. After 25 years, you will have saved 175,000 kroner /$32,327.80 USD. With the correct wastewater solution, you can really save money and protect the environment.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

This article does not appear in The Last Straw and is original content.

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

402.483.5135, <thelaststraw@thelaststraw.org> www.thelaststraw.org

INSULATION

The R-value used for straw-bale walls is R-30. Most conventional stick-built construction has an R-value of around 15 with as high as R-30 in ceilings.

Testing under controlled conditions allows the researcher to estimate the thermal resistance to heat flow through the material. This is expressed as an R-value. (R = resistance) R-value is the inverse of U-factor, or conductivity. U-factor is a measure of Btu/(hr. s.f. °F), or British thermal units per hour, per square foot of material, per degree Fahrenheit of temperature difference between the two sides of the material.

Conclusions from the document Thermal Performance of Straw Bale Wall Systems available at www.ecobuildnetwork.org/strawbale.htm

Tests have shown a range of values from R-17 (for an 18-in. bale wall) to R-65 (for a 23-in. bale).

Analysis at Oak Ridge National Lab, among other places, has shown that R-values for insulation materials used in standard walls are generally much higher than the R-value for the wall as an assembly of disparate materials. Joe McCabe recently postulated that the same phenomenon could account for the difference between the high values from his testing of bales and the lower values obtained in the 1998 Oak Ridge test of a straw-bale wall system. While it is possible that the relatively low densities where bales abut each other might contribute to greater heat loss than would be measured through an individual bale, it is unlikely that this would account for the entire difference. This difference between bales and bale walls is nothing like the difference between standard insulation and what is found in stud framed walls (insulation voids, thermal bridges, uninsulated headers, and other faults).

It is noteworthy that all tests of straw-bale wall systems prior to the Oak Ridge test in 1998 had potentially significant shortcomings and should not be considered particularly reliable. The last Oak Ridge test had no identified deficiencies and is considered by most to be an accurate determination of the thermal resistance of straw-bale walls. ORNL determined the R-value to be R-27.5 (or R-1.45/inch), or R-33 for three string (23-in.) bale wall systems. Shaving a bit off the top just for conservatism’s sake, the California Energy Commission officially regards a plastered straw-bale wall to have an R-value of 30.

A final note is a reiteration of a point made earlier: it matters little whether the final truth about the R-value of straw bales walls is R-33 or R-43 or even R-53. Above R-30, the differences are minor and will usually be overshadowed by windows, floors, doors and ceiling/roof details.

Whatever the value, it is at least three times better than the average -in.R-19-in. wood stud-wall system.

FIRE

In July 2006, the Ecological Building Network in California funded and oversaw the following ASTM E119-05a – Straw Bale Fire Tests done in Texas. Both walls withstood the fire and hose stream tests, as described below.

(Documents are available at www.ecobuildnetwork.org/strawbale.htm)

One-hour Fire Resistance of a Non-Loadbearing Wall w/ Earth-Plaster Coating.

A 12 ft x 14 ft non-loadbearing wall constructed with 7.5 pcf rectangular wheat straw bales stacked in a running-bond pattern, clad on each surface with 1-inch of earthen-plaster, produced, assembled and tested as described in the documentation, successfully met the conditions of acceptance as outlined in ASTM Method E119-05a Fire Tests of Building Construction and Materials for a fire endurance rating of one hour.

Two-hour Fire Resistance of a Non-Loadbearing Wall w/ Cement-Stucco Coating.

A 10 ft x 10 ft non-loadbearing wall constructed with 7.5 pcf rectangular wheat straw bales stacked in a running-bond pattern, clad on each surface with 17 GA stucco netting and 1-inch of cement/stucco, produced, assembled and tested as described in the documentation, successfully met the conditions of acceptance in ASTM Method E119-05a Fire Tests of Building Construction and Materials for a fire endurance rating of two hours.

The EcoBuilding Network’s Board of Directors is currently Ann Edminster (Pacifica, California) Architect, author of Efficient Wood Use in Residential Construction-in., and co-chair of the development committee for LEED(TM) Residential standards.

Bruce King (San Rafael, California) Director, Founder, Structural Engineer, author of Buildings of Earth and Straw-in. (1996), -Making Better Concrete-in. (2005), and Design of Straw Bale Buildings-in. (2006); Sarah Weller King (San Rafael, California) Secretary and Treasurer Peter Loafer (Boulder, Colorado) Attorney and property developer; Drew Moran (Palo Alto, California) President, Drew Moran Construction; Anne Tilt (Berkeley, California) Architect and partner, Akin-Tilt Architects; Carol Vilonia (Santa Rosa, California) Architect, contributing columnist for Natural Home magazine, co-author of Natural Home Remodeling (2006).

MOISTURE

From House of Straw – Straw Bale Construction Comes of Age, U.S. Department of Energy, Energy Efficiency and Renewable Energy, April 1995. www.eren.doe.gov/buildings/documents/strawbale.html

Will the bales rot? Without adequate safeguards, rot can occur. The most important safeguard is to buy dry bales.

Paint for interior and exterior wall surfaces should be permeable to water vapor so that moisture doesn’t get trapped inside the wall. Construction design must prevent water from gathering where the first course of bales meets the foundation. Even if straw bales are plastered, the foundation upon which the bales rest should be elevated above outside ground level by at least six inches or more. This protects bales from rainwater splashing off the roof.

From Moisture properties of straw and plaster/straw assemblies by Dr. John Straube in Canada as a result of testing done there. John holds a joint appointment as Associate Professor in both the Department of Civil Engineering and the School of Architecture at the University of Waterloo and teaches courses in structural design, material science, and building science to both disciplines. At the university, John is also the director of the Building Engineering Group. John is a founding principal of Building Science Consulting, a frequent contributor to buildingscience.com.

Based on the test data and literature review, several conclusions can be drawn:

1. A 450 mm (18-in.) thick straw bale should have a vapor permeance of approximately 110 to 220 ng/ Pa•s•m2 (2 to 4 US perms).

2. Cement: sand stuccos are relatively vapour impermeable. In fact a 38 mm (1.5-in.) thick cement : sand stucco may act as a vapor barrier (i.e., have a permeance of less than 1 US Perm).

3. The addition of lime to a cement stucco mix increases permeance. As the proportion of lime is increased, the permeance increases. Pure lime: sand stuccos are very vapor permeable. The permeance of a 38 mm (1.5-in.) thick cement : sand stucco can be increased to 5 or 10 US Perms by replacing half the cement with lime and to 15 to 30 US Perms by using a pure lime : sand stucco. The addition of even a small amount of lime (0.2 parts) may increase the permeance of cement stucco dramatically (e.g., from under 1 to 3 to 6 US Perms).

4. Earth plasters are generally more permeable than even lime plasters. The addition of straw increases the permeability further. A 38 mm (1.5-in.) thick earth plaster can have a permeance of over 1200 metric perms (over 20 US Perms), in the same order as building papers and house wraps.

5. Applying an oil paint to a moderately permeable 1:1:6 stucco will provide a permeance of less than 60 metric perms (1 US perms) and thus meet the code requirements of a vapour barrier.

6. Earth plasters were not found to have significantly different water absorption than cement and lime stuccos. The earth plasters, regardless of density and straw content, resisted 24 hour of constant wetting easily, although the topmost 1/8-in. of surface became quite muddy. In a real rainstorm this behavior may cause erosion.

7. Lime washes appear to be somewhat useful for reducing water absorption while not reducing vapor permeance. The lime wash over earth plaster did not dramatically lower water absorption but will increase the mechanical strength of the plaster after wetting, i.e., they will increase the resistance to rain erosion.

8. Based on Minke’s and Straube’s earlier tests, siloxane appears to have little or no effect on the vapor permeance of cement, cement:lime, lime, and Moisture Properties of Plaster and Stucco for Strawbale Buildings EBNet BalancedSolutions.com 34 earth plasters while almost eliminating water absorption. The use of siloxane can be recommended based on these earlier tests.

9. Sodium silicate did not seem to have much impact on water uptake or vapor permeance. This additive may hold earth plaster together, or increase its erosion resistance, but as tested it had no noticeable impact on moisture properties.

10. Linseed oil at 2% in an earth plaster mix is not a very effective water repellent and does act to restrict vapor permeance somewhat. It may add some strength to an earth plaster in the wet state. Heavy applications of linseed oil to the surface of finished earth plaster will, based on Minke’s tests, reduce the water absorption to almost zero, but will markedly decrease vapor permeance.

11. The test methods described here appear to provide repeatable results, and in general compare well to previous tests on different samples by both the same (Straube) and different researchers (Minke).

Gernot Minke founded the Research Laboratory for Experimental Building at Kassel University in Germany in 1974, studying straw-bale construction and other sustainable building techniques, low-energy and passive house construction, and green roofs. He is also an independent architect and adviser for building ecology.

The full article can be accessed at the EcoBuilding Network’s web site www.ecobuildnetwork.org/strawbale.htm

INSECTS, VARMINTS AND VERMIN

Will the bales rot? Without adequate safeguards, rot can occur. The most important safeguard is to buy dry bales. Fungi and mites can live in wet straw, so it’s best to buy the straw when it’s dry and keep it dry until it is safely sealed into the walls.

Paint for interior and exterior wall surfaces should be permeable to water vapor so that moisture doesn’t get trapped inside the wall. Construction design must prevent water from gathering where the first course of bales meets the foundation. Even if straw bales are plastered, the foundation upon which the bales rest should be elevated above outside ground level by at least six inches or more. This protects bales from rainwater splashing off the roof.

Will pests destroy the walls? Straw bales provide fewer havens for pests such as insects and vermin than conventional wood framing. Once plastered, any chance of access is eliminated.

House of Straw – Straw Bale Construction Comes of Age, U.S. Department of Energy, Energy Efficiency and Renewable Energy,

April 1995

www.eren.doe.gov/buildings/documents/strawbale.html

CODES

There are provisions within the building codes that allow building with bales. David Eisenberg, Development Center for Appropriate Technology (DCAT) in Tucson, Arizona (www.dcat.net), shares these citations from codes that pertain to straw-bale design and construction as an alternative materials, design and methods of construction and equipment. David has been involved with codes issues related to strawbale and other natural building materials and methods for 15 years or more, and as a member of the board of UBC, USGBC and other organizations working with building codes and green building programs.

You can use this information to answer questions codes officials and other regulatory agencies may have.

From the 2003 International Energy Conservation Code (IECC)

SECTION 103

ALTERNATE MATERIALS — METHOD OF CONSTRUCTION, DESIGN OR INSULATING SYSTEMS

103.1 General. The provisions of this code are not intended to prevent the use of any material, method of construction, design or insulating system not specifically prescribed herein, provided that such construction, design or insulating system has been approved by the code official as meeting the intent of the code. Compliance with specific provisions of this code shall be determined through the use of computer software, worksheets, compliance manuals and other similar materials when they have been approved by the code official as meeting the intent of this code.

From the 2006 IECC

SECTION 103

ALTERNATE MATERIALS — METHOD OF CONSTRUCTION, DESIGN OR INSULATING SYSTEMS

103.1 General. This code is not intended to prevent the use of any material, method of construction, design or insulating system not specifically prescribed herein, provided that such construction, design or insulating system has been approved by the code official as meeting the intent of this code. 103.1.1 Above code programs. The code official or other authority having jurisdiction shall be permitted to deem a national, state or local energy efficiency program to exceed the energy efficiency required by this code. Buildings approved in writing by such an energy efficiency program shall be considered in compliance with this code.

From the 2003 International Residential Code (IRC)

R104.11 Alternative materials, design and methods of construction and equipment. The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code. Compliance with the specific performance-based provisions of the International Codes in lieu of specific requirements of this code shall also be permitted as an alternate.

R104.11.1 Tests. Whenever there is insufficient evidence of compliance with the provisions of this code, or evidence that a material or method does not conform to the requirements of this code, or in order to substantiate claims for alternative materials or methods, the building official shall have the authority to require tests as evidence of compliance to be made at no expense to the jurisdiction. Test methods shall

be as specified in this code or by other recognized test standards. In the absence of recognized and accepted test methods, the building official shall approve the testing procedures. Tests shall be performed by an approved agency. Reports of such tests shall be retained by the building official for the period required for retention of public

records.

From the 2006 IRC

R104.11 Alternative materials, design and methods of construction and equipment. The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code. Compliance with the specific performance-based provisions of the International Codes in lieu of specific requirements of this code shall also be permitted as an alternate.

R104.11.1 Tests. Whenever there is insufficient evidence of compliance with the provisions of this code, or evidence that a material or method does not conform to the requirements of this code, or in order to substantiate claims for alternative materials or methods, the building official shall have the authority to require tests as evidence of compliance to be made at no expense to the jurisdiction. Test methods shall be as specified in this code or by other recognized test standards. In the absence of recognized and accepted test methods, the building official shall approve the testing procedures. Tests shall be performed by an approved agency. Reports of such tests shall be retained by the building official for the period required for retention of public records.

From the 2006 IBC

104.11 Alternative materials, design and methods of construction and equipment. The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved.

An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, at least the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety.

104.11.1 Research reports. Supporting data, where necessary to assist in the approval of materials or assemblies not specifically provided for in this code, shall consist of valid research reports from approved sources.

104.11.2 Tests. Whenever there is insufficient evidence of compliance with the provisions of this code, or evidence that a material or method does not conform to the requirements of this code, or in order to substantiate claims for alternative materials or methods, the building official shall have the authority to require tests as evidence of compliance to be made at no expense to the jurisdiction. Test methods shall be as specified in this code or by other recognized test standards. In the absence of recognized and accepted test methods, the building official shall approve the testing procedures. Tests shall be performed by an approved agency. Reports of such tests shall be retained by the building official for the period required for retention of public records.

INSURANCE AND FINANCING

See http://sbregistry.greenbuilder.com – the International Straw Bale Registry sponsored by The Last Straw journal, Greenbuilder.com, Development Center for Appropriate Technology and the Texas straw-bale association as a resource and research database pertaining to straw-bale building, including buildings open for tours and visits, descriptions of design, construction, materials, special features and those who were involved in the building project, including homeowners, owner/builders, insurance, mortgage lenders, builders, architects and others.

When planning and building a straw-bale building, it is best to make contacts early in the process about liability insurance coverage during construction as well as homeowners coverage after the building is completed.

Homeowners insurance is available for straw-bale homes and insurance coverage for other straw-bale buildings is available also. Independent insurance agents and companies may be more likely sources, but many other companies offer homeowners and liability insurance.

Many straw-bale buildings are owner-financed or built on a pay-as-you-go basis, but as strawbale and natural building become more popular and generally accepted many structures have been financed through mortgage lenders, banks, credit unions, state and federal funding for housing, and other sources.

Contact your local sources to determine your best options. You may want to prepare detailed financial calculations and a budget for the project before approaching these groups and institutions. And you will need to be well versed about straw-bale projects in your immediate area, identify comparables from real estate companies, if possible, and have already contacted your local codes official about regulations and permits so that you know the project can be permitted.

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

This story is a reluctant one about a house comprised of both wood-framed and straw bale walls lost to a fire. The structure was built over a longer period of time than most main-stream homes.  The different phases incorporated the most appropriate materials at the time for the owners. We are excluding specific reference to the owners and the location of the building due to privacy concerns. For this article we will say that the building is in the central U.S. at approximately 8000 ft elevation and the Owner’s name is Bob. In the end, it really does not matter who owns the home or exactly where it is. What we will focus on is the performance of the bale walls in the fire, the aftermath, and how the owners and insurance company feel about the whole incident.

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

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

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

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

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

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

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

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

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

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

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