There are foam animals that expand from a tiny capsule to several times their size (link). I would like to see a product similar to this. The foam is packed in a wrapper under vacuum in flexible sheets. When the bag is broken the foam sucks in air. Moisture or oxygen from the air activate the foam so it hardens in a few hours into a sheet of insulating material. It would be ideal for roofs. You roll it on and nail it down. Let the nails stick out a little. The nails puncture the wrapper and disappear in the rising foam. Their heads are fully enclosed and they firmly anchor the sheet to the rafters. Since the original material was flexible you can get really big sheets on a roll and have fewer seams to worry about. Unlike plywood the flexible sheet will also adjust to warped rafters. The chemist could tune the material to pass steam, but repel liquid water (like Gore-Tex). If that is not possible the outer layer may need an extra coating with a sealant.
-- kbecker, Dec 04 2003

(?) Foam creatures http://www.thebeanp...co.za/products.html
[kbecker, Oct 04 2004, last modified Oct 21 2004]

Polycel insulating foam http://www.gesealan...other/polycel.shtml
In a can. [kropotkin, Oct 04 2004, last modified Oct 21 2004]

Blown insulation http://www.cookingu...ions.html#cellulose
For cavities. [kropotkin, Oct 04 2004, last modified Oct 21 2004]

Lots more foam http://www.marinefoam.com/
In rolls, rigid sheets, and pourable polyurethane. [kropotkin, Oct 04 2004, last modified Oct 21 2004]

During the fitting process, exactly when would you cover it in umberellas?
-- dobtabulous, Dec 05 2003


WIBNI, unless you have a particular material in mind. The foam animals you refer to don't become archetecturally rigid as far as I know.
-- phoenix, Dec 05 2003


Sounds very complex. Why not use existing foams in a spray or pourable foams, rather than having to do all that nailing?

The only new aspect seems to be the "increases vastly in size whilst preserving shape" aspect. I'm not convinced you could find materials with the right chemical properties to absorb air and expand whilst staying in a nice rectangular shape. (I agree with phoenix on the WIBNI call.)
-- kropotkin, Dec 05 2003


kbecker/phoenix: it doesn't necessarily need to harden to be an effective insulator.
-- DrCurry, Dec 05 2003


True, but I read the original idea as a building material. The author still contends that the foam should harden, though now I can't see why.
-- phoenix, Dec 05 2003



random, halfbakery