i mean, what do you use to make it stay put? glue? nails?
These are sheets of foam cut to size, they use a piece or steel wire to hold the foam up its cut some what longer then the width of the bal so it bends forcing it to dig into the joist.
Steel spreaders may be cheapest (as described in other answer) but many roofs have shingle nails sticking out,a couple dabs of caulking,glue,you're done! Be sure anything you use is compatible with your foam,some will just MELT it. Good Luck! DrJ
