Paul sits back down with Mike Haasl and Beau Davidson to talk some more about mycelial insulation panels.
Wood and straw bales have an r-value of 1-2/inch – not that much, but quite a bit when a bale is 18” thick. Mycelium boards r-value depends on its density and how completely it consumes its substrate, but is usually comparable to rockwool which has an r-value of between seven and twelve, and up to 17 per inch. Rockwool has an r-value of 5/inch.
In order to keep the mycelium from trying to turn your house into a compost pile, it has to be baked. This presents a problem because you have to bake the inside of a thermal insulator. More problems come from trying to cut the stuff, with the best fungus for insulation so far also being very difficult to cut from a combination of simple toughness, its fibrous nature, and its tendency to gum up sawblades. Water jet cutting is out of the question, seeing as adding water to the insulation might make more mushrooms rather happy.
The substrate will need to be inoculated with spores, then kept warm and moist for about 10 weeks before being ready to cook. When done, it’s non-flammable, mice don’t like it, repels insects, and resists mould. Plus, the substrate produces mushrooms while it’s growing, which is just added value, although getting more than one crop will mean having to delay getting the insulation.
When ready to cook, the mycelium can be removed from their trays as they’re rigid, and cooking the insulation requires the temperature to reach 200F for about four hours to stop it from growing. Killing the spores requires the temperature to be higher, but they need water to grow, so unless there’s water seeping into your house, there’s not much chance of mushrooms sprouting from your walls, and if there is, there’s bigger problems.
Dr. Hugh Gill Kultur
Eivind W. Bjørkavåg
Suleiman, Karrie, and Sasquatch
Jocelyn Campbell Wade Luger
havokeachday Bill Erickson
Julia Winter, world's slowest mosaic artist
G Cooper Penny McLoughlin
Polly Jayne Smyth
It sounds like seal is more important than R-value in this red cabin situation. I wonder if mycelial batts could be grown in a form that interlocks, something along the lines of tongue-and-groove. I don't know the technical term for these. Then gravity would help keep a seal to some degree.
___\--__\--__\-- kind of thing
It is tempting to think of a way to grow the insulation in place. Keeping a tiny, skiddable or wheeled house toasty warm and moist in a workshop is conceivable. But then there's the problem of your wood frame for that skiddable house turning into more non-structural mushroom substrate.
I wonder if this could be used in place of billboards/pond liner for wofati=making--and here the mushrooming and baking process could be done on site somehow against dirt rather than against wood. It's not quite water-tight but it might slow it down enough for the need? The baking part is trickier, but a) maybe it isn't necessary in this situation, just burying it under 2 feet of soil might deprive it of oxygen it needs to stay alive; b) it could be heated with a fresnel lense maybe, or with a temporary container being put over it and a rocket stove filling that space to make a temporary oven going up to 200 degrees. It could be really, really thin as long as it keeps most of the water out of the dirt below; thinner should shorten the growing time and baking time, I imagine.
Regarding the red cabin, overall, I'm wondering why the red cabin couldn't just be replaced by another tipi? or have a tipi eat it and thereby seal it? or be supplemented by a second tipi for winter and then just be a 3-season structure? I hear that you just really feel depressed at the thought of plywood.
Community Building 2.0: ask me about drL, the rotational-mob-grazing format for human interactions.
Location: Massachusetts, 6b, suburban, nearish coast, 50x50, full sun, 40" year-round even distribution