What is the difference between the open-cell and closed-cell spray foam?
The open-cell polyurethane foam has a lower density and weighs about 0.4-0.6 lbs per cubic feet. It expands more than 100 times of its original size. It is semi-rigid and is used usually indoors. The closed-cell polyurethane foam has a higher density and weighs about 1.5.2 lbs per cubic feet. It expands 35-50 times its original size. It is more rigid and used at places where it has to bare higher burdens (for example on flat roofs where foot traffic is usual).
