subject: Spray Foam Insulation Techniques [print this page] Spray Foam Insulation is used in residential and commercial buildings to provide then thermal insulation. It is applied using various spraying methods. Thermal spray foam insulation is easy to apply. It is sprayed onto or into the underside of the roof within the attic/loft space, and dries to rigid foam. The effectiveness of spray foam insulation is generally determined by its R-value, but this does not take consider construction or local environment factors.
Before getting spray foam insulation done it should be determined whether it is beneficial to use 0.5 lb./cu. ft., open cell foam, or 2.0 lb./cu. ft. closed cell foam. This decision makes difference in cost, application methods, and performance. The major difference between open cell and closed cell spray foam is that in open-cell foam tiny cells of the foam are not completely closed they are broken and air is filled in these spaces where as in Closed-cell foam differs in that all of its tiny foam cells are closed and packed together and all of its tiny foam cells are closed and packed together. They are filled with a gas that helps the foam rise and expand and become a better insulator.
Open cell foams typically weigh in at 0.4 to 0.5 lb./cu. ft. Closed cell foam for insulation applications range in density from 1.7 lb./cu. ft. to 2.0 lb./cu. ft. Roofing applications typically use a 2.8 to 3.0+ lb./cu. ft. Some polyurethane foam are molded into decorative interior molding and painted or stained for a simulated wood effect. These foams have comparatively higher density which is generally 30 lb./cu. ft. to 40 lb./cu. ft. density range.
Open-cell foam should be avoided in below grade or in flotation applications where it could absorb water leading to decreased thermal performance. Open-cell SPF has an R-value around 3.5 per inch and typically uses water as the blowing agent. Closed-cell SPF has an R-value of around 6.0 per inch and uses high R-value blowing agents. Closed-cell foam compared has higher strength, higher R-value, and has greater resistance to the leakage of air or water vapor.
Both varieties of foam is used for insulating buildings and the choice for which to use can depend on many of the factors discussed above foam should be chosen depending upon place where spray foam is applied or strength of insulation needed. Both types of foam are commonly used in most building applications and the choice for which to use depends on many of the factors discussed above.
