INSULATE WITH FOAM

IT'S A GREAT ALTERNATIVE TO FIBERGLASS

- MARK PETERSEN

Closed-cell polyurethane spray foam has some outstanding qualities it has a high R-value, it expands into hard-to-reach areas, and it's resistant to water, mold and insects. Heck, it can even add structural support.

However, it is expensive, so we spoke with a couple of manufacturers and some pro insulators about where and when to use it, when to call in a pro with a truck-mounted unit, and when a DIY kit is the best option. We also assembled some great installation tips to help you spray safely and get the best value for your investment.

We used the Froth-Pak Insulation 210 two-component, low-pressure kit. It has an R-value of 6 per inch.

FOAM IS MEASURED IN BOARD FEET

Most two-part spray foam kits have a number assigned to them: 120, 200, 210, 600, etc. That number usually indicates how many board feet the foam will cover. So, a 200 kit will cover 200 sq. ft. at 1 in. thick.

SEALANT VS. INSULATION

Closed-cell spray foam sealant looks just like foam insulation, but it's not the same thing. Sealant is formulated to seal cracks and voids, or the perimeter of stud spaces before you install fiberglass insulation. Sealant should not be used to fill larger cavities because it loses its fire-retardant properties when applied in thick layers.

OPEN-CELL VS. CLOSED-CELL FOAM

Two kinds of spray foam are available: open and closed. Closed-cell foam costs more than open-cell, but the properties of closed-cell make it more popular. It's more resistant to water and can provide an air and vapor barrier (depending on the thickness). It also provides nearly double the R-value per inch over open-cell.