air sealing bath tub plumbing

Air sealing bath tub plumbing is crucial to avoid air leaks and moisture.

Air leakage associated to bathtubs sitting against un-sheathed studs or to holes in the top and bottom plates are particularly common and should be fixed.

Bath Tubs Air Leakage These penetrations are very problematic since they are also a source of moisture. See images (from DOE), depicting the areas that should be air sealed and insulated.

Insulation, sealing and materials

Before installing (or reinstalling) any tub you should insulate carefully the exterior walls and seal the wall surface behind it.

Do get it properly, use polyethylene foams and sheet good materials.

After installing the drain, its penetration should also be sealed with sheet goods (drywall, plywood...) and spray foam (or a silicone caulk, if the penetrations are small).

Sealing behind the tub or shower, especially if it is on an exterior wall Penetrations in the floor and ceiling (namely those connected with the soil stack – the main drain pipe) should also be properly sealed.

Use a good polyurethane-based foam.

Pay also attention to possible electrical penetrations, connected to bath tubs. They too should be properly sealed.

See: Caulking Electric