In this video, This Old House plumbing and heating contractor Richard Trethewey shows how to find and fix a bathroom leak.
1. Inspect bathroom for water leaks. Check areas around the tub, tub drain, tub overflow, shower door and toilet.
2. Snap chalk lines on ceiling below and use a reciprocating saw to cut out the damaged drywall.
3. Inspect the backside of the damaged drywall for water damage.
4. Measure the distance from the water damage to the nearest plumbing fixture to determine the source of the leak.
5. Perform a water-leak test with handheld shower by spraying water around the shower door.
6. Check for water leaking out of shower or tub and into the ceiling below.
7. Attach a snap-on door sweep to the vertical edge of the shower door to create a watertight seal.
8. Use utility knife or grout saw to scratch out the old grout and caulk from joint between floor and tub.
9. Apply a bead of clear silicone caulk to joint between floor and tub.
10. Patch ceiling with a new piece of drywall; attach the drywall with 1¼-inch drywall screws.
11. Finish the drywall patch with joint compound and joint tape.
12. Once the drywall is finished, apply one coat of primer and two paint topcoats.