• 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.
    • 2 to 6 hours, depending on the severity of the leak
    • About $20 to $40
    • Difficulty: Moderate
      replacing damaged, soggy drywall can be a messy, tedious chore

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      Video Directory

      Selected Topic/Section

      Tools List

      • chalk line
        Chalk line, used to snap cutting lines on existing ceiling
      • reciprocating saw
        Reciprocating saw, for cutting out water-damaged ceiling
      • utility knife
        Utility knife or grout saw, used to remove old grout from joint between floor tile and tub
      • caulk gun
        Caulking gun, for applying silicone caulk
      • drill
        Cordless drill, used to drive in drywall screws
      • drywall knife
        Drywall taping knives, used to finish drywall ceiling patch
      • paintbrush
        Paintbrush and paint roller, for priming and painting drywall patch

      Shopping List

      1. Door sweep, for creating watertight seal along vertical edge of shower door

      2. Silicone caulk, for sealing joint between floor and tub

      3. Drywall, used to patch ceiling below bathroom4. Drywall screws, for attaching new drywall patch to ceiling joists

      5. Joint compound and drywall tape, for finishing new drywall patch

      6. Primer and paint topcoat, for covering drywall patch