No House Wrap.....?
After Katrina, many of the homes looked like this picture. a 2 inch average of Closed Cell 1.8 (or 2.0) pound is what you need. DO NOT use .5 (half Pound) you need a vapor "Diffusor" like house wrap. Since you are retro fitting an old garage or something, you just need closed cell, cost more than the .5 pound foam but it is the correct way to build. The foam will fill every crack so you will need to manage that aspect of the Spraying. The size of the cracks can let foam "spray" the "car" on the other side of the wall so filling over a hole with tape and the proper plastic will leave you with a paintable surface of foam. if you are in a Climate Zone 7 you could go up to 2.5 inch "average" of closed cell, but it cost more...
After Katrina, many of the homes looked like this picture. a 2 inch average of Closed Cell 1.8 (or 2.0) pound is what you need. DO NOT use .5 (half Pound) you need a vapor "Diffusor" like house wrap. Since you are retro fitting an old garage or something, you just need closed cell, cost more than the .5 pound foam but it is the correct way to build. The foam will fill every crack so you will need to manage that aspect of the Spraying. The size of the cracks can let foam "spray" the "car" on the other side of the wall so filling over a hole with tape and the proper plastic will leave you with a paintable surface of foam. if you are in a Climate Zone 7 you could go up to 2.5 inch "average" of closed cell, but it cost more...
