Get a pressure tester so you can verify for yourself that it can push out 3.5 Lbs. Make a test box. Build a 16" O.C. box out of 2x4's. Cover the back with OSB or something and mesh off the front. Make it tall enough to give you a sense of how filling it all up works. I'll be easier to tear the cellulose out of a bad test box than an entire cavity.
|