Strawbale construction is a natural building technique with ancient origins as far away as the African plains. The strawbale construction we are familiar with today has its roots in the advent of the mechanical baler in the 1850s. Because pioneers of the Western plains lacked the timber resources available elsewhere in the country, strawbales were found to be a practical, readily-available alternative in many places, especially where the soil was not suited to building sod houses. In recent years, strawbale construction has quickly become a popular sustainable, and renewable solution for building ecologically-conscious structures. Strawbale structures built by Strawbale Studio in Michigan.
Some of the advantages of strawbale construction include:
- A high insulation value (R-30 or more)
- Recycling what is often considered a “waste” product
- The materials are natural, biodegradable, and have a low embodied energy
- The walls are thick and the bales are shapable, which allows for the creation of window seats, benches, shelves, and more
- The results are beautiful!
Strawbale walls are formed by stacking rectangular bales on top of each other like bricks. In “load-bearing” strawbale construction, the strawbales make up the entirety of the wall and bear the weight of the roof or upper floors of the building. Load-bearing is more commonly used in arid climates, like the South West.
The buildings Strawbale Studio use “post & beam” construction; wooden posts and beams bear the load while the strawbales serve as “infill” for insulation. Post abd beam construction is considered most suited to this climate, because the frame and roof is built first, and the bales have protection during installation and plastering. Additionally, post and beam is able to hold the winter snow loads which put weight on the roof.
MICHIGAN RESIDENTIAL CODE 2015 (MRC2015)
Michigan Strawbale Code MRC2015-1 MI Appendix S was adopted directly from the International Residential Code (IRC) and can be viewed at the national IRC public access code site. Michigan Strawbale Code is up for revision in 2018…so make sure you are looking at the latest MI code. Also see the Light Straw-Clay code adopted by Michigan from the IRC Code.
Below are the page numbers if you are looking at the Michigan Residential Code (MRC)
- Light Straw-Clay Construction (App R, pp 835-837) and
- Strawbale Construction (App S, pp 839-849) precede about a dozen index pages at the end. See also the state energy code requirements,
- Energy Efficiency – State requirements (Ch 11, pp 437-455).
Sam Newman provided the following:
Light straw-clay code: This makes me feel pretty positive about the possibility of repeatable and permitted energy retrofits using no foam or plastic, but instead packing straw-clay into the stud bays of an uninsulated house from the outside and then plastering over it.http://codes.iccsafe.org/app/book/content/2015-I-Codes/2015%20IRC%20HTML/Appendix%20R.html
Straw bale code (as of 2018, the Michigan straw bale code is word-for-word the same as the national code (IRC)
ARTICLES & VIDEOS
Build It With Bales – free online book. Excellent for basic building.
More Straw Bale Building : A Complete Guide to Designing and Building with Straw
by Chris Magwood and Peter Mack
Despite growing interest in the technique, however, most straw bale books focus on “selling” the dream of straw bale building, but don’t adequately address the most critical issues faced by bale house builders. More Straw Bale Building is designed to fill this gap. It leads the potential builder through the entire process of building a bale structure, tackling all the practical issues: finding and choosing bales; developing sound building plans; roofing; electrical, plumbing, and heating systems; building code compliance; and special concerns for builders in northern climates.
Serious Straw Bale: A Construction Guide for All Climates
by Paul Lacinski and Michel Bergeron
This book provides the metaphorical nuts and bolts of straw bale construction for homes and other buildings. Unlike many other straw bale construction books on the market, this one looks at building design issues from the perspective of straw bale builders and considers the particular needs of the medium. Several different techniques are discussed, focusing much information on the needs of those building in wet and/or cold environments. Many illustrations, some color, and several project profiles demonstrate the theories discussed.
Straw Bale Details A Manual for Designers and Builders
by Chris Magwood and Chris Walker
Design of Straw Bale Buildings by Bruce King The State of the Art details Serious. This was recommended by Laura Bartells who does this professionally. It is quite involved with data and testing. Very detailed.
The Natural Plaster Book by Cedar Rose Guelbreth and Dan Chiras, illustrated by Deanne Bednar
(Banner Credit: Red Moon Sanctuary)