Like its name suggests, open-cell foam is made up of tiny bubbles that are interconnected. The bubbles hold air, which provides insulation value — typically between R-3.5 and R-4 per in.
Like closed-cell foam, open-cell foam expands to fill gaps and cracks as soon as it's applied. But instead of curing to a hard, smooth-surfaced mass, open-cell foam has a spongier feel. And like a sponge, it will absorb moisture. Since insulation loses R-value when wet, it's not advisable to use open-cell spray foam in damp environments like basements and crawl spaces. It can be sprayed between rafters or studs, but its low R-value won't provide much total insulation value in a confined space. Open-cell foam is usually less expensive to install that closed-cell foam.
You may be surprised at the versatility of spray foam! Older buildings can have SFI sprayed in place of existing insulation for even greater energy savings. It’s also great for tight spaces and crevices in basements, under the home and much more.
Spray foam may look thin when it’s first sprayed on an area, but it gradually expands, making it great for a wide range of applications where you need an airtight fit that still provides for excellent insulation from Dayton’s climate.