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SoyThane Spray Urethane Foam Made Easy, Do it Yourself, (DIY) | Do It Yourself Spray Foam, DIY Spray Foam, Soy Foam DIY, Urethane Foam. It is made partly from renewable soy, uses compressed air as the propellant, is very compact to ship saving embodied energy, and is cheaper per board-foot than jug-style foams unless you need a small amount. The proprietary dispensing gun is included in the order and the foam material is much cheaper, so the more you need the less it costs.
I had a nearly hour-long talk with the founder (Tom, I think) about all things spray foam about a year ago. Very knowledgable & friendly older guy. Only thing not a 100% win for me is that their current formulations are not designed to be flame-retardant, although he said they are working on that.
I am considering an encapsulated attic, which requires at least R30 low permeability insulation topped with an ignition barrier in my area. My plan was to get recycled foamboard from ebay seller "insulationdepot" (for both the attic and my heat storage tank), cut it to fit between the roof rafters, then top with a bit of spray foam to make up the remaining R-value, form an ignition barrier and to seal the gaps.
I could still spray some intumescent paint on top for the ignition barrier, but it would be nice if the foam could be the barrier. I've put this project on "simmer" while doing other things, hoping soythane will add a flame retardant. Anyone compared their products to propellant jug types?
Craig