Straw Bale Construction

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A Love of Straw Bale Construction

 

Living Shelter Design is one of only a handful of design firms in the Pacific Northwest with a solid background in Straw Bale Construction.  It was the catalyst that turned our head to focus on ecological building design so many years ago, and has a special place in our hearts. As it’s affectionately said in Straw Bale circles, we were “Bit by the Bale Bug” and carry a lifelong affliction. Of course we approach it with reason, knowing this method isn’t for everyone or every location. However, there is something about it that sings to us and others – perhaps you hear the song too!

With over 20 projects constructed and more than a dozen hands-on workshops under our belt, we have experience and knowledge to pass on to others and can help a straw bale project run smoothly. We’d love to help out with your project, or teach you to build with bales yourself.  If you would like to be added to our mailing list for upcoming workshops and other pertinent information, please visit www.livingshelter.com/contact-us and sign up.

 

Frequently Asked Questions

 

What is so good about straw-bale building?

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 simple to build with, making them the perfect material for owner-builders and community groups. With a “barn-raising” type party, walls for a single-family home often will go up in one day. A straw bale home is beautiful and sculptural. The thick walls create wide window sills, and are easy to carve into niches and curves.

Straw is a non-toxic, natural material meaning healthier indoor air. 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 often burned as a waste product. Baling the straw for construction can reduce air pollution, and provide local farmers with additional income. Straw bales create such soundproof walls, one Nebraska pioneer family was found playing cards in their kitchen, oblivious to the tornado blowing through town!

How is a straw bale building constructed?

There are basically two types of wall systems. Originally, in turn of the 20th 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 buildings of small to moderate size. Dry, dense bales are stacked 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 its place of origin.

However, 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 in-fill wall systems. 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.

Won’t the bales rot?

Liquid moisture can be a problem in any type of wall. Proper detailing at the floor, windows, and roof overhangs will stop liquid moisture from entering the bales. Once a good stucco finish is applied to the outside, some rain hitting the wall is not a problem. Locations with heavy wind-driven rain will benefit with wood or metal siding over a single coat of stucco. In all cases, it is important to select a stucco material with proper permeability, so your walls can allow moisture vapor to escape. As long as the bales are kept dry, you should not have any problems with rot or fungi.

Are straw bale buildings more susceptible to fire?

No, in fact they are more fire resistant 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 is high in 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. The same is true with insects. If you seal your wall surfaces properly, you should have no problems with pests.

Do straw bale houses cost less to build?

Not necessarily. The cost of the wall system in a house is typically about 10 to 12% of the total cost of construction, so the walls are not really the determining factor in your overall budget. If you want a typical American house, with all the plumbing and appliances and a contractor to build it, the costs can actually be a little more than same as a home built with other wall materials. Your life-cycle costs, however, will be much less. As straw-bale pioneer Judy Knox said, “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 and investing your own sweat and ingenuity, 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?

While some cities and many counties in Washington State have straw bale buildings they are proud of, others are more cautious about it. The 2015 Residential Building Code has a chapter on prescriptive straw bale construction, but this code release has not yet been adopted by any jurisdiction in our tri-state area. Current building codes do allow for alternative materials if a licensed architect and engineer are involved in preparing your plans, as their professional stamp of approval transfers liability of the home’s integrity to them. If you are going to build in a jurisdiction that has allowed straw bale construction in the past, it should be easy to get a permit with properly prepared plans. If this is a new material for your jurisdiction, it may take extra effort to convince the local building official that this alternative material will perform as well as the standard frame construction they have become used to. We have gotten the first straw bale homes through the permit process in many jurisdictions, and early education and collaboration are key.

Is there insurance and financing available?

Some insurance groups have insured bale homes at preferred rates, while others are more skeptical. You’ll want to shop around, and we can provide you with some agents that have historically been supportive. The same stands true for lenders. You may need a licensed contractor involved in your project to secure a construction loan. The costs of building a home out of alternative materials, such as straw bales, are being incorporated into some cost-estimating books, so well-informed insurers and appraisers are able to calculate their value. The missing link for appraisers has been finding local comparable sales, since there are still few of these homes in any geographical area. To overcome this some people have listed “wood framed with cellulose insulation” as the wall type on loan documents. As pre-owned bale homes come to the market, lenders are recognizing the value in them, with straw bale homes often selling for up to 10% above the local market.

What are the best resources to learn more?

There are many sources of information out there, and three 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. The Last Straw Journal has long been publishing the latest research and findings from the straw building community at large, and there are now several Facebook pages and Linked-In groups, as well. And consider attending one of our workshops to round out your knowledge with a hands-on experience – there’s nothing like being immersed in the process. You might even get “bit by the Bale bug” and become another straw bale advocate!