Wall Repair Behind Tile
The shower corner that has been pulling away from the wall for two years. The single hollow-sounding tile near the valve that finally cracked open and revealed the gray, soft drywall behind it. The closet on the other side of the master shower wall whose paint has been bubbling at the baseboard since last winter. The mildew bloom that no amount of bleach will clear because it is coming through the porous substrate, not living on the surface. Wall repair behind tile is the trade for what is happening one layer in from the finish surface — wet drywall or backer board cut out, framing dried, mold treated, substrate replaced with cement board or Schluter KERDI-Board, real waterproofing membrane reinstalled, and the wall prepped for re-tile. Starting at $900 for a small drywall patch behind a single tile up to $3,500 for a full backer-board and membrane rebuild behind a shower wall. Honest scope — when the moisture source is an active in-wall plumbing supply or drain leak, a licensed Washington L&I plumber handles their portion FIRST, and Handis returns for the wall and waterproofing rebuild after.
Service
How Wall Repair Behind Tile Works
Seven sequential steps from the on-arrival diagnostic open through substrate cut-out, mold treatment, dry-down, substrate replacement, membrane install, and prep for tile reset — the sequence we follow on every wall-behind-tile repair.
Diagnostic Walk and Controlled Opening
Tap-test the tile field around the failed area for additional hollows. Press-test the substrate from any accessible back side. Moisture meter on the wall surface. Remove a 12-inch by 12-inch controlled opening centered on the failure to inspect substrate, framing, and any active wetness or mold.
Diagnose the Moisture Source — Plumber or Handis Scope
Source tracing from the opening. Failed caulk seam letting water through the joint for years (Handis scope). Failed waterproofing or original substrate that was never waterproofed (Handis scope). Active in-wall plumbing supply or drain leak (licensed Washington L&I plumber FIRST). When the source is plumbing we name the licensed sub on the quote and stage the rebuild for after their portion closes.
Cut Out the Wet Substrate
Wet or moldy drywall, greenboard, or cement board comes out. Cut to the centerline of the nearest stud on each side, and to a horizontal line above and below the wet area plus 6 inches of margin. The framing under the wet substrate gets a visual and struck-with-a-hammer test for water damage.
Treat Mold with Quaternary Ammonium and Dry Down
Visible mold on framing or substrate gets a quaternary ammonium cleaner (Spartan NABC, Diversey Virex, or equivalent) on the full ten-minute label dwell. Rinse, dry with a heat gun until the moisture meter reads under 12 percent on the framing. For extensive black mold across multiple stud bays we will recommend a certified mold remediation contractor.
Replace Substrate with Cement Board or Schluter KERDI-Board
Standard cement backer board (Hardibacker, Durock, USG Tile Backer) fastened with cement-board screws every 6 inches on the panel field and 8 inches on the perimeter — or Schluter KERDI-Board (waterproof foam panel) installed with KERDI-Fix sealant at the seams when integrating with an existing Schluter system. Panel sized to the opening with full bearing on framing.
Install Real Waterproofing Membrane
Schluter KERDI sheet membrane bonded to the cement board with thinset, seams overlapped and taped with KERDI-Band. Or RedGard liquid waterproofing brushed on in two coats with fiber-reinforcement fabric at all changes of plane (corner, curb, niche). The membrane is the continuous barrier that stops water from reaching the cavity again.
Prep the Wall for Tile Reset
Level the membrane surface. Mark out the tile layout matching the existing field. Stage the wall for tile reset (a separate scope under tile and grout repair). Most customers book the tile and grout repair scope together with the wall repair as a single coordinated project; we name both portions on the quote.
Wall Repair Behind Tile Pricing
Final pricing depends on the size of the wet area, the substrate type behind the tile, whether mold remediation is required, whether a licensed plumber is in the loop for an active in-wall leak, and whether the tile reset is bundled with the wall repair. Licensed-plumber sub fees pass through transparently with the line item named. Request a free estimate for an accurate quote.
Send us photos of the failed tile area and any visible bubbling paint on adjacent walls — we will tell you the scope.
Why Handis for Wall Repair Behind Tile
The most-common mistake on any shower or tub-surround repair is the rebuild that uses cement board as if it were waterproofing. Cement board is dimensionally stable under moisture exposure (it does not swell, crumble, or rot the way drywall does), but water passes straight through it. The original 1995-to-2010 standard was cement board with mastic-set tile and no waterproofing membrane behind — and that install has a 10-to-15-year service life before the moisture reaches the framing and the wall has to come out. Every Handis wall-behind-tile repair gets a real waterproofing membrane bonded to the cement board (Schluter KERDI sheet with KERDI-Band seams or RedGard liquid brushed on in two coats with corner reinforcement fabric). The membrane is the layer that turns a 10-year repair into a 25-year one.
Estimate
Tell us where the failed tile area is (master shower corner, hall tub surround, niche, valve area), any visible bubbling paint on the back side of the wall, and the approximate age of the tile install if you know it. Send phone photos of the failure and any adjacent-wall paint damage. We will tell you on the response whether it is a Handis-only visit or needs a licensed plumber sub in the loop, and we will quote both portions line by line.
Customer Reviews
Recent wall repair behind tile reviews from verified Handis customers.
Mildew bloom behind the master shower wall in the closet. Tech opened the shower corner, found the original cement board had never been membraned and the drywall behind it was wet and moldy two feet up. They cut out the wet drywall, treated the studs with a quaternary cleaner, replaced with KERDI-Board, did fresh Schluter membrane, prepped for tile. The tile bundle came next visit and the closet wall has been bone dry for over a year.
Single cracked tile near the valve. Tech opened the area, found about one square foot of soft drywall behind, no active plumbing leak just a years-long failed caulk path. Replaced the drywall with cement board, RedGard membrane in two coats with corner fabric, prepped for the tile reset they did the following day. Bundled the tile and grout repair so it was one project, one warranty.
Active leak inside the wall behind the guest-bath shower valve. Handis was honest on arrival — said it was a licensed plumber call first, not theirs. They named a Washington L&I plumber, the plumber came in for the supply line repair, then Handis returned to rebuild the substrate with new KERDI-Board, a fresh Schluter membrane, and prepped for the tile reset. Two contractors, one coordinated project, transparent line items.
1998 shower with the cement board install that had no membrane. We had been getting mildew at the same corner for years and no amount of bleach would clear it. Tech said the substrate was probably wet, opened it, confirmed — full two-stud-bay rebuild with KERDI-Board upgrade and Schluter membrane. The mildew has not come back.
Bubbling paint on the bedroom wall behind the master tub surround. Tech said the source was almost certainly the tub-surround caulk path, opened the surround side, confirmed wet drywall, did the substrate rebuild and membrane on the bathroom side, then patched the bedroom drywall after the cavity dried. Two-sided repair, one visit, one warranty.
Frequently Asked Questions
Common questions about Handis wall repair behind tile.