Can insulating concrete be used for footings?
One of the tough questions about ‘super-insulated’ building is what to do about footings? Some say don’t mess with them, too risky just take the heat loss hit. Some have used foam under footings. Those opposed to foam point out it’s propensity to ‘creep’ under long term stress and that it’ll deform substantially under rated stress conditions. An alternative, that I’ve seen little discussion of, is lightweight concrete mixed with perlite as the aggregate. http://www.perlite.com/concretemixdesigns.PDF
Why not make the footings themselves out of perlite concrete? It is inelastic, way stronger than footing pressures on the soil and, in my case at least, plenty of safety margin to support the concrete walls and house above under total peak load situations. With a 12″ deep footing of 8-1 perlite I’ll have r20+ footings! What am I missing?