The key to patching torn drywall paper is to seal it first with an oil- or shellac-based sealer (KILZ Original and BIN are two brands). These are available in spray cans or liquid that you can ...

If there’s no wood, staple it right to the drywall. Seal the gap between the flue and metal flashing with special high-temperature silicone caulk. Don’t use spray foam here. Form an insulation ...