Closed cell foam can also increase the racking.
Attic closed cell foam insulation.
Open cell foam weighs 1 2 pound per cubic foot and closed cell weighs 2 lbs per cubic foot.
Polyurethane foam spf insulation and we are frequently asked to march 2007 i jlc i 1 insulating unvented attics with spray foam closed cell polyurethane foam provides the insulation air barrier and vapor retarder necessary for an unvented attic assembly closed cell polyurethane foam provides the insulation air barrier.
Insulating value and strength open cell foam has an r value of about 3 5 to 3 7 per inch while closed cell foam has an r value of about 6 per inch.
This medium density spray foam is a closed cell spray foam that is typically used where there is the need for r value insulation per inch possible.