I recently insulated my entire house with foilfaced fiberglass batts, and I found a good tool for cutting the stuff down to size — hedge shears. That’s right, but they have to be sharp. They easily cut through R-19 foil or kraft-paper faced batts even when they’re fully lofted. You don’t have to compress the insulation to cut it, as you would if you used a utility knife.
Ron Smith, Sunol, CA