Frequently asked questions about straw bale construction

What is so good about a straw-bale house?

Plenty! Straw bales offer excellent insulation, over twice as much as a standard stick-framed house. This saves energy, which saves money and is kinder to the environment. They are also low-tech and simple to build with, making them the perfect material for owner-builders and community groups. With a "barn-raising" type party, it's common for the walls for a single-family home to go up in one day. A straw-bale home is beautiful and sculptural. The soft edges from the bales create a sensual surface, imparting a feeling of warmth and comfort. The thick walls create wide window sills, and are easy to carve into niches and curves.

Straw is a non-toxic, natural material which actually allows the walls to breathe, creating cleaner indoor air by allowing pollutants a means of escaping to the outside. Straw bale walls are quiet - in fact, they create such soundproof walls, that one Nebraska pioneer family was found playing cards in their kitchen, oblivious to the tornado blowing through town! A house built with straw bales typically uses less lumber, reducing the impact on our forests. Straw is annually renewable, and abundant wherever grain crops are grown, and is in fact burned as a waste product in many parts of the world. Baling the straw for construction can reduce air pollution, and provide local farmers with an additional source of income.

How is a straw bale building constructed?

There are basically two types of wall systems. Originally, in turn of the century homes on the northern plains, bales were used as the structural system. Many of these buildings are in good condition today, and the method is still used for one-story buildings of moderate size. Dry, dense bales are stacked in a running bond, like big bricks, and pinned with rebar or bamboo. The roof then rests on a wood plate system at the top of the wall, which is secured to the foundation. This type of load-bearing construction is often termed "Nebraska Style".

Due to several factors, another method is often used. A simple frame of posts and beams carry the structural load of the building, while the bales act as walls and insulation. The bales are stacked in the same way as the load-bearing option, but placed either inside, outside, or in between the posts. These are termed frame and bale or in-fill buildings. They are usually easier to permit, since building officials are familiar with how a frame reacts to different loading conditions, and they can allow more design flexibility.

Are straw bale buildings more susceptible to fire?

No, in fact they are more fire resistive than a typical framed house. Individual straws will burn, but a straw bale is so compressed, there is not enough oxygen for combustion. It is like trying to burn a phone book. Straw also has a high silica content, causing the surface of the bale to char, and block the flame from reaching farther into the bale. In laboratory tests in New Mexico, a plastered bale wall easily passed a two-hour fire rating, which is required for commercial construction.

Aren't there problems with mice and insects?

There is no food value to straw, since the seed heads have been removed at grain harvest. No animal or insect will eat it. A mouse might tunnel into a bale wall that is not protected by plaster or stucco, but a mouse could get into a framed wall just as easily if there is a hole in the siding or drywall. If you seal your wall surfaces properly, you should have no problems with pests.

Won't the bales rot?

Liquid moisture can be a problem in bale walls, as with any type of wall. As long as bales are kept dry, you should not have any problems with rot or fungi. Proper detailing at the floor, windows, and roof overhangs, helps to stop liquid moisture from entering the bales. Once the stucco is applied to the outside, rain hitting the wall is not a problem. However, it is important to select a stucco material with proper permeability, for your walls to breathe and allow moisture vapor to escape.

Do straw bale houses cost less to build?

This is a difficult question to answer. The cost of the wall system in a house is typically about 10 to 15% of the total cost of construction, so the finishes are really the determining factor in your overall budget. It is possible to build a straw bale house for less, if you do much of the work yourself, and use salvaged material. If you want a typical American house, with all the plumbing and appliances and a contractor to build it, the costs will be pretty much the same whether the walls are of wood studs or straw bales. Your life-cycle costs, however, will be much less. As straw-bale pioneer Judy Knox says, "Straw is a superior material for a comparable cost."

This is not to say you have to spend the same amount of money on your house as the average homeowner. By acting as your own contractor, investing your own sweat and ingenuity, and possibly salvaging construction materials, you can save on costs substantially. Straw bale walls are easy to raise, and the rest is manageable if you keep the project fairly simple. Living Shelter can help you organize a wall raising, or could hold one or more workshops at your construction site, to train you and others in the specifics of building with straw bales.

What about getting a permit?

In the state of Washington, straw is treated as an "experimental material" at this time, and while some cities and counties have straw bale buildings they are proud of, others are more cautious about it. If you plan to build in a jurisdiction that has allowed straw bale construction in the past, you should find it fairly easy to get a permit. If not, it may be your challenge to convince the local code authority that this alternative material will perform as well as the standard frame construction they have become used to. There are some building officials in California, New Mexico, and Arizona who are willing to talk with your jurisdiction, in an effort to convince them to grant a permit. Engaging a licensed architect and engineer in your presentations may be necessary, as their professional stamp of approval transfers liability of the building's integrity to them.

Is there insurance and financing available?

Some insurance groups have insured bale homes at preferred rates, and others are following suit. The same stands true for lenders, although you may need a licensed contractor involved in your project to secure a construction loan. Click on http://sbregistry.greenbuilder.com to find information on insurance and lending companies that have been involved with bale buildings in the past. The costs of building a home out of alternative materials, such as straw bales, are now incorporated into standard cost-estimating books, so insurers and appraisers are able to calculate their value. And as pre-owned bale homes come to the market, lenders are recognizing the value in them, including Fannie Mae and HUD; straw bale homes are often selling for up to 10% above the local market price!

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What are the best resources to learn more?

There are many sources of information out there, and two books come to mind most readily. The Straw Bale House by Steen and Steen is a great place to begin, a good overview with lots of pictures. Build It With Bales by MacDonald and Myhrman is the definitive owner-builder manual, filled with loads of practical advice, wisdom and humor. "Serious Straw Bale: A Home Construction Guide for All Climates" by Paul Lacinski and Michel Bergeron provides the most current information on building practices in many climates. Consider subscribing to The Last Straw, the only periodical dedicated to straw-bale construction, and well worth the $28 annual subscription price (call 402-483-5135, email thelaststraw@thelaststraw.org or mail PO Box 22706, Lincoln, NE 68542). There is a question and answer forum on the internet you can subscribe to, by sending an e-mail to strawbale@listserve.repp.org with only "subscribe strawbale digest" in the body of the message. You can research past topics by visiting http://solstice.crest.org and clicking on "discussion groups", then on "strawbale construction". And consider attending one of our workshops to round out your knowledge with a hands-on experience. There is nothing like getting out and doing it to get a more complete understanding of how the system works.

Inside:

Straw Bale Home Q&A
Ecological Glossary
Ecological Links

Terry Phelan of Living Shelter Design is an architect deeply committed to reducing the environmental impact of her buildings. She is an active member of the Northwest Ecobuilding Guild, and her work in load bearing straw bale structures is exceptional.

Habib John Gonzalez
Director, Sustainable Works
Nelson, British Columbia, Canada

Van Cleve Workshop 2004

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