Straw Bale House in the City, Part 3: Costs and Straw Bale Density



The Straw Bale in the City 3-part series walks readers through the codes, costs, and construction of a straw-bale build on a non-rural property. Part 1 covers issues with building codes and managing expectations of city inspectors. Part 2 looks at straw bale design through the lens of a test wall, while in Part 3, readers learn the density and moisture considerations that can plague straw-bale construction without proper planning while also covering costs of this project.

I had a somber tone as we drove back from the hay lady Laurie’s barn full of straw. I couldn’t believe that we had went to a completely different supplier and found exactly the same density straw bale. I used my phone to search for dense straw bale suppliers and found only one supplier out of New York. I wasn’t sure what to tell the developer, who so badly wanted us to build a straw bale house for her company. I hadn’t been able to locate a third party engineer to work with us during construction of the straw bale house, nor had I been able to find straw bales dense enough to meet code.

As we drove back to our Farm, Bob and I started discussing how a straw bale would have to be made in order for the straw bale to meet the building code for density. I reviewed the Michigan Residential Building Code Book’s section on straw bale construction and under the section labeled “Density”, it read:

Bales shall have a dry density of not less than 6.5 pounds per cubic foot. The dry density shall be calculated by subtracting the weight of moisture in pounds from the actual bale weight and dividing by the volume of the bale. Not less than 2 percent and not less than five bales to be used shall be randomly selected and tested on site. (2015 Michigan Residential Code, Page 840, Section AS103.5 Density)

At first glance, the way that the code is worded seems confusing; however, the formula is relatively simple once you understand how the formula works. Below is an actual entry from the notes that we gathered as we tested our straw bales during the mock up:

Straw Bale #3

Subscribe Today - Pay Now & Save 64% Off the Cover Price

50 Years of Money-Saving Tips!

Mother Earth NewsAt MOTHER EARTH NEWS for 50 years and counting, we are dedicated to conserving our planet's natural resources while helping you conserve your financial resources. You'll find tips for slashing heating bills, growing fresh, natural produce at home, and more. That's why we want you to save money and trees by subscribing through our earth-friendly automatic renewal savings plan. By paying with a credit card, you save an additional $5 and get 6 issues of MOTHER EARTH NEWS for only $12.95 (USA only).

You may also use the Bill Me option and pay $17.95 for 6 issues.

Canadian Subscribers - Click Here
International Subscribers - Click Here
Canadian subscriptions: 1 year (includes postage & GST).

Facebook Pinterest Instagram YouTube Twitter flipboard

Free Product Information Classifieds Newsletters