A medium density, closed cell SPF weighing approximately 2 lbs. per cubic ft. when fully cured. It is also spray applied as a liquid to a substrate and expands approximately 35 to 50 times its original volume to form a rigid, structural SPF insulation with a compressive strength of 15-25 PSI. 2 lb. Foam-LokTM has an R-value of 6.0 per inch (aged R-value).