Do you think closed cell spray foam adds any strength to a wall? Matt Risinger rigged up a test to see if it does.Closed cell foam is a rigid foam, sometimes referred to as a two-pound foam. In this video, the house contains 2" of closed cell foam sprayed along the walls. In order to test the added strength of the spray foam, Risinger concocted a test to show the added strength. He made a small box of with AdvanTech sheathing nailed to 2 x 4s. There are three boxes one control with no sheathing, one box with a "picture frame" of closed cell foam, and a box with 2" of closed cell foam. He used a sledge hammer and attempted to dislodge the sheathing from each of the three boxes. Check out the video to see if the closed cell foam added strength to the AdvanTech sheathing.