Foundation
Insulation
by Alex Wilson Part I
It is estimated that only about 5 percent
of all the buildings in America have
insulated foundations. Collectively, the
heat lost through basement walls, concrete
slabs and crawl spaces from our 100
million or so residential buildings
represents half a quadrillion Btu —
roughly half the current nucleargenerating
capacity in the U.S.
When the notion of energy-efficient
construction first caught on in the early
70s, an interesting "insulation evolution"
began. First we addressed ceilings—they
were easy. We could simply add another
layer of fiberglass batts or blow in the
stuff.
Then came the walls. Two-by-sixes
weren't that much more expensive than
two-by-fours, and we could achieve a
much higher R-value. Two-by-eights
allowed for even more, as