Foam insulation, usually urethane, can be injected
into wall cavities or sprayed onto roof or floors. Once applied,
it expands and sets in about a minute. After it sets, it shrinks
slowly for several weeks. Properly applied, shrinkage is less
than 5 percent. Like rigid boards, foam insulation has the advantage
of high R per inch. Similarly, it shares the disadvantage of requiring
a fireproof covering material when installed inside the home.
Foam insulation, usually urethane, can be injected
into wall cavities or sprayed onto roof or floors. Once applied,
it expands and sets in about a minute. After it sets, it shrinks
slowly for several weeks. Properly applied, shrinkage is less
than 5 percent. Like rigid boards, foam insulation has the advantage
of high R per inch. Similarly, it shares the disadvantage of requiring
a fireproof covering material when installed inside the home.
