It also seals every potential leak—then hardens into a rigid, durable shell that strengthens the frame of the home. This isn’t latex-based kid stuff, though. Like other polyurethane-based foams, applying this two-part mixture requires training and safety gear. The company recommends that installers undergo a complete physical before being exposed to the product, followed by regular checkups. Gaco Western’s heaviest “2 pound” spray-in-place wallfoam mix has an R-value of about 7.5 per inch, with an expected aged R value of about 6.22.