One of the most common concerns we hear from homeowners is about spray foam insulation and roof leaks. It usually goes like this: “If I use foam and I have a leak one day, I won’t know it because the foam will hide it.” That’s a very real and very understandable concern, and it’s worth unpacking because not all foam behaves the same way. Closed-cell foam is extremely dense, strong, and highly efficient. It’s fantastic for adding rigidity to walls and crawlspaces,...