Random Spray Vs. Rigid Insulation Thoughts

[o1marc]

After much research I'm starting to lean away from spray foam. Spray kits run around $1/sf for 1" thick, or $1.50 for 1-1/2" thick. I was able to cut polyiso to tightly fit the curved spaces. It runs $10 for a 4' x 8' sheet or $.31/sf or $.94/sf.

The R factors are the same between the 2.

Some good info on why spray foam is not good inside "metal boxes":

https://www.insulation4less.com/Insu...ternative.aspx

[brokedown]

Rigid foam is much less expensive for sure! I'm using a little polyiso where I need something thin and flexible but mostly XPS because it's R value is stable over a range of temperatures.. Polyiso performance drops with cold temperatures.