How Long Will Polyurethane Spray Foam Last?

Benefits

• Sprayed polyurethane foam has a comparatively high R-value among insulation materials. The R-value is the unit of a material’s resistance to heat. It is calculated by dividing the thickness of the substance by its thermal conductivity. The higher the resulting number, the better the substance is as an insulator. Sprayed polyurethane foam has an average R-value of between 7 and 8 per inch. In comparison, fiberglass batts have an average of between 3.14 and 4.3, depending on the density of the batt, while blown-in cellulose averages between 3.6 and 3.9 per inch. As sprayed foam comes as a liquid, it is effective at insulating hard-to-reach areas and at conforming to the shape of any space.

Longevity

• Sprayed polyurethane foam should last for as long as the building in which it is installed, provided it does not become damaged. Because it conforms to the contours of an area, where it hardens and expands after installation, it minimizes air gaps through which moisture and insects can penetrate. This limits degradation. Cleaning and recoating the foam every decade or so should ensure its durability for the lifetime of the building.

Installation

• Proper installation of polyurethane foam is one of the keys to securing its longevity. If it is correctly installed, air gaps will be minimized, preventing moisture penetrating the foam and degrading it. As such, spray urethane foam insulation is typically performed by professional installers. However, competent DIY-ers can hire the requisite machinery and install the foam themselves. It is applied with either hand-held spray guns or pressurized-air machines. In both instances, protective clothing and face masks should be worn. Air ducts and vents should be protected so that they can be accessed after installation is complete, and a cardboard barrier set across the door to the room to minimize foam getting into the home.

Precaution

• Spray polyurethane foam insulation must be covered with a fire resistant material after installation. It is treated with fire resistant chemicals to prevent combustion, but can smoulder and emit noxious fumes if it comes into contact with naked flames. Drywall is a common covering. It may also have an acrylic or silicone coating applied to protect it from damage.