HI there Mick
I found your name on the web while doing a search for straw bale construction in Maine.
My partner, XXXX and I are getting ready to build again yes at the ages of 60 and 66! We have a bit of land in XXXX and want to build as off the grid as we can We also love straw bale, but haven’t been able to find out where to get straw bales anywhere near here We thought perhaps you could give us some leads Do you know of any local farmers who grow and bale straw and will sell it ?? any hints you can give us will be much appreciated!
Meanwhile Happy Spring!
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Hi XXXX:
I should start off by noting that Aimee and I are both scientists, not straw bale advocates, so we do objective reporting on our work, including domestic experiments. We have been gently advising homebuilders against building with straw in Maine now since we got done with our bale house experiment. The main reason is the lack of suitable cheap bales, and the fact that you will almost certainly have to build a straw-wrap house, rather than a "Nebraska style." Because you will have to build some kind of timber frame to support the roof, and because straw is expensive and has to be trucked far in Maine, there is no great cost savings and there are increased climate emissions. In particular, we paid up to $7 a bale, and the lowest price we got, at $2, was for very few bales. I would expect to pay an average of $3.5 for a 40-50 pound bale.
To my mind, these facts negate the whole argument for straw -- that it's a cheap locally-produced product for both structure and insulation that would otherwise go to waste. Straw is neither particularly cheap nor locally produced in Maine. It's also labor intensive, particularly at the plastering stage, and labor is not cheap, while plastering skill is hard to come by.
You will discover additional difficulties with insurance and possibly building codes enforcement, none of which are necessarily insurmountable, but it makes little sense to take them on considering the above. There will also very likely be difficulties later with critters in your walls.
If instead you used cellulose (a fully recycled product) or recycled foam board insulation, or both (see below) you would get the insulation benefits, reduce costs, avoid critters and codes-enforcement officers, and be able to insure your home for less.
Cellulose is R3.8 per inch. An 8-inch stud wall cavity (really 7.5 inches) filled with cellulose (on 24-inch center) is R28.5. Two inches of recycled polyisocyanate or urea formaldehyde foam board on the outside of the sheathing adds around R24, providing R52.5, enough insulation for a passive solar house. These specifications, carried out by a proper contractor, are suitable to pass muster as a "normal" home with insurance companies. If you home build, you may have to use "surplus lines" insurance, but the costs per unit coverage will still be less than for a bale home.
Some natural builders balk at using either kind of insulation, worried about venting of toxic chemicals contaminating room air. The fire retardent in cellulose is borax, which is toxic, but doesn't actively vent in any toxic form, and will in any case be behind drywall. The recycled foam board will be fairly stable, because it is old, and any venting will be to the outside, not inside.
Having noted all this, I will mention that our advice generally has little effect on prospective home-builders who are already commited to straw bale. This seems to be one of those cases of advocacy or possibly religion defeating science.
If this is the case, straw bale vendors can be found, and with luck you may get a good price. The best chances are found with hay dealers who make a living trucking hay from regions where it is in surplus, such as Aroostook County, to places where it is in shortage, such as the suburban Boston/Portland region. Hay dealers can usually find straw bales too, and a tractor-trailer load can be easily arranged in season.
The dealer I use is Mr Beem of Beem Farm in Newport, Maine.
I have written this information out several times in the past few years. I hope you don't mind if I post this email to my blog so I don't need to do so again.
Regards,
Mick