Remember that first little piggy who built his house out of straw? We didn’t think things ended up too well for him, so we asked Andrew Morrison, an expert on straw bale construction, to set the record straight.
“A friend of mine talks about the fourth little pig (a story that very few people know). He built his house out of stone (foundation), sticks (framing), and straw (insulation). Not only was his house the strongest, but it was the most energy efficient!” Andrew says.
Independent testing has shown that straw bale construction is more fire resistant, more soundproof, stronger, and more energy efficient than conventional construction, he says.
“There is not much we need to do as straw bale builders and enthusiasts to ‘set the record straight.’ The record speaks for itself,” he adds.
In order to share the latest news and information and evangelize about straw bale construction, Andrew co-founded StrawBale.com with his wife in 2004. Here, he discusses why that first little piggy was actually on to something.
Tell us about StrawBale.com … when and why did you start your site?
My wife and I started StrawBale.com in 2004 because we saw a need in the market to provide accurate information to the growing world of straw bale construction. There was a lot of misinformation (and great information as well) available, and discerning which was which was difficult for someone not well versed in the methods. We wanted to provide a place for people to get all of their questions answered by an expert in a timely manner. We also wanted to provide active training through DVDs, books, and hands-on workshops for those interested in taking it to the next step.
What is straw bale construction? When did you become passionate about it?
Simply speaking, straw bale construction is a technique in which straw bales are used in one of two general ways to build a home.
1. Bales are used as the structural members of the walls and no framing is necessary to support the roof loads. This is called “load bearing construction.”
2. Bales are used as in fill insulation in between or around framing members in the wall. This is called “in fill construction” and is the more popular and versatile option of the two.
I became passionate about straw bale construction in 1996 while living in Colorado. It was clear to me as a builder, from the start of my career, that there was too much waste in residential construction, and I wanted to be a part of the solution rather than the problem. Although already a “Green Builder” before it was coined and popular, I knew that there must be something even better out there. After many workshops and many pages of books, I found where my passion was most alive: in straw bale construction.
How do straw homes work? What are the components?
As I mentioned earlier, there are two types of straw bale construction: load bearing and in fill. Those differences not withstanding, the basic premise is that the bales are stacked in the walls, wrapped in a welded wire mesh (some choose not to use it, but I much prefer the added strength and convenience of using the mesh) and plastered with a natural plaster, my favorite being natural hydraulic lime. The electrical and plumbing is all installed in the walls with special care being taken to isolate any plumbing from direct contact with straw to mitigate any potential water damage in the future. Additionally, wood backing can be placed in the walls to support cabinets and other heavy, hanging items. That backing is placed behind the plaster so is not visible in the finished product. The homes look like a plaster building from the outside, and one cannot tell they are anything different than a conventional home; however, from the inside, the window wells are deep and the walls are beautiful. In fact, there is nothing quite like the “feel” of a straw bale home.
What are the advantages of using straw as a building material?
A straw bale wall assembly is three times more fire resistant than conventionally built walls (per ASTM testing), three times as soundproof, three times as energy efficient, has superior strength in terms of wind resistance and projectile resistance (tornado debris, for example), and is made of natural, non off gassing materials.
What about disadvantages?
The labor is intensive and long winded, so construction costs can be higher when comparing square foot costs. In addition, the plastering process takes skilled labor, and that can be difficult to find in markets where plaster and stucco work is not common. Home loans and insurance are a little bit harder to find than they would be for a conventional house; however, they are not impossible to find. It just takes some extra leg work for the homeowners.
What are the most important things to consider when building a structure out of straw?
Moisture. Hands down, moisture is the biggest and I dare say only enemy of straw bale construction. Extreme attention must be given to all wall penetrations, window and door openings, as well as roof and foundation designs. Making sure these details are handled properly is important in any home; however, the implications can be much more drastic in a bale home if the details are missed.
How important are gutters to homes built using straw?
Gutters or some way to control roof run-off are very important on a straw bale home as water and moisture are the only true enemies of straw bale construction.
What types of gutters would you recommend for homes built with straw?
I have used seamless gutters on most homes; however, I have also seen other ideas such as rain shedding slats employed. The exact type of gutter is not as important as the quality of the craftsmanship. As long as the gutters are effective and kept free of excessive debris, they will provide years of protection for your straw bale walls.
What’s the most innovative straw bale structure you’ve come across recently?
I would say that the designs put out there by David Arkin and Anni Tilt of Arkin Tilt Architects provide some of the most innovative straw bale structures I’ve seen lately. They are working hard to make these homes fit the desires of mainstream homeowners in a way that showcases the incredible benefits of straw bale construction without letting go of the design aesthetics desired by so many modern homeowners. Their work is inspirational to many and has been awarded by such publications as Fine Homebuilding.
What do you think would surprise people the most about the conventional building materials we use today?
I think it would be a combination of two things: the levels of toxicity that exist in so many common building materials and the excessive waste that a typical home build generates. Both of those issues have not improved much in the last 20 years and may, in fact, have gotten worse. Because labor costs are rising (a good thing, mind you), many builders are looking for ways to hold their prices steady and, unfortunately, in many cases that means simplifying construction through more wasteful techniques.
How do you think we’ll build homes in the future?
My hope is that people will start embracing two schools of thought: natural building, using materials that don’t off gas and cause long-term health problems for the home’s occupants as a trade-off for simple building techniques, and building to what I call the “scale of our humanity.”
Our homes have gotten too big. In fact, the average home size has increased steadily since 1973 and now sits above 2,600 square feet for home sizes averaging under three people per home. That is too big and wastes not only materials during construction, but also energy and materials required for the long-term upkeep of those homes.
I recently presented at a TEDx Event in Colorado Springs about the importance of minimizing our housing needs and simplifying our lives in such a way that we can enjoy our lives more. This is my hope for everyone, and I believe it has a lot to do with how we build our homes. You can view that TEDx Talk here:
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