I am just finishing up a report on a home constructed of straw bales. Third structure in the county to be constructed of straw bales. I did a search at yahoo.com for straw bale construction and found several sites. By the way, there are structures over 100 years old still standing and still in use in the sand hills of Nebraska originally constructed of straw bales (where it rains frequently and has high humidity). Before insulation was invented, homes in the midwest had straw packed inside the exterio walls for insulation. The first home here in my county was built about 8 years ago, has 1,000 square feet, two bedroom, one bath, no heating system, evaporative cooler for cooling system. Their total utility bill is $40 per month. Don't have the cooler on during the day while every one is gone, even when it is 110 degrees outside, turn it on when they get home and the house is completely cool in five minutes. Occasionally turn an electric space heater on for a few minutes in the winter. My subject is not complete, lacks a heating and cooling system, flooring in the living room and bedrooms, and lacks counter tops; so they haven't had a utility bill yet. Of course there are not any sales, so I am using homes constructed of other energy efficency materials like adobe, rasta/eterna block, etc. The web sites I found were:
http://www.eren.doe.gov/buildings/document.../strawbale.html
http://www.azstarnet.com/~dcat/QandA.htm
http://www.azstarnet.com~dcat/res2.htm
http://www.azstarnet.com/~dcat/appraise.htm
http://www.azstarnet.com/~dcat/codes.htm
be sure and check out:
http://www.azstarnet.com/~dcat/slides.htm
http://www.strawhomes.com
http://www.thelaststraw@strawhomes.com
My subject has concrete slab floor, telephone cross arm beams for the post and beam construction to support the roof structure, stuccoed exterior, drywall and wood paneled interior, insulated metal roof. The exterior walls are 2' thick, so their window wells and doorways are 1 1/2" deep.
I measured the exterior walls, the depth of the door ways and then on my sketch show two walls--the outer dimension and used the depth of the doorways to the exterior of the door jamb to place the interior wall, which I used to calculate the livable area. That method allow about 6" for wall depth that is included in the livable area. I have described in my addendum my method of calculating livable area and also that the adjustment per square foot to the comparables is slightly lower than typical due to the differances in calculating square footage for the subject and comparables. Something similar to my adjustments for manufactured housing, since typically the only thing I have to base the manufactured home comparables on includes the tongue and my subject does not include the tongue.
By the way several of the articles on the internet describe the home as being very safe regarding fires. If you ever watched a hay bale burn, you would understand why. A stack of hay bales can smolder for days and weeks before it actually burns. They can take as long or longer to burn than a heap of old tires.
So have fun! I did because it was a challenge and I do enjoy challenges.