Spray foam insulation
After getting a quote for $500 for spray foam to go into a 3 x 12 area 4 inches deep (have one of my knee wall- slanty ceilings opened up, I looked around at DIY options. I dont think Id want to bother with the two-part products that costs a few hundred dollars, but what I can't figure out is why I cant just spray some Great Stuff in there. According to my reading, I want closed cell foam.... AND, I'm also reading that Great Stuff *IS* closed cell. So why is it that I shouldnt use it?
Question: can foam insulation go into wall cavities or does the wall have to be opened up? I thought the latter (since the foam expands) but somewhere I read that it can just go right into a wall cavity that is not opened up.
Guess I just need a reality check about foam insulation.