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Schluter Home Additions & ADU: The Los Angeles Owner’s Guide
If you bought a home in Los Angeles planning to add square footage with Schluter waterproofing and uncoupling membranes, you’re looking at an installed cost of roughly $53,100 to $153,400 for a home addition, and $106,200 to $259,600 for a full ADU build. Those are real numbers for this market in 2026, not national averages. When a Schluter product fails mid-project or years later, the usual discovery is a cracked tile, a soft spot underfoot, or water staining at a transition. We carry Schluter-compatible membranes, drains, and edging profiles on our trucks, and we match the failed part to your specific system before we quote anything.
Which Schluter Models This Applies To
Schluter makes systems under a handful of names you’ll see stamped on the product: DITRA, DITRA-HEAT, KERDI, KERDI-BOARD, and the matching KERDI-KM drain assemblies. Each line has distinct specs. DITRA uncoupling membranes come in 1/8-inch thickness for tile and stone, while KERDI-BOARD panels run from 5/16-inch up to 2 inches thick for shower walls and benches. If you’re mid-ADU and a membrane has delaminated or a drain flange cracked, you can’t just grab any replacement. The drain grate, bonding flange, and waterproofing collar have to match the exact KERDI version installed, because the fleece weave and bond strength differ between generations. One gotcha we see regularly in Los Angeles: a contractor installs a 48-inch KERDI-SHOWER tray, then someone patches a corner with a generic foam board. It looks fine for about a year, then the seam fails under thermal movement. We always check the embossed code on the back of the existing piece before matching it.
Styles & brands we work with
Signs Your Schluter Home Additions & ADU Is Failing
- Water staining below the addition’s floor line in the crawlspace or on the ceiling of the room under it. That means the membrane overlap or a corner seal has failed, and water is traveling beyond the waterproofed envelope.
- Grout cracks that follow a straight line across the tile, especially at transitions between old and new framing. Uncoupling membrane that never got embedded properly lets structural movement telegraph straight into the tile.
- Loose or “rocking” tile near a floor drain. In a Schluter system, the drain body is bonded to the membrane; if the tile lifts there, the bond between the grate and the bonding flange has usually broken.
- A soft, spongy feel underfoot in an ADU bathroom or kitchen. This points to water intrusion into the subfloor, often from a failed seam at a curb or wall junction where the KERDI fabric was not lapped the full required 2 inches.
- Musty odor inside built-in cabinets or behind vanities, with no visible leak. We find failed corners behind KERDI-BOARD installations where screws were placed without KERDI-FIX, and moisture has been wicking silently for months.
Replacement Cost & What’s Included
For a Schluter part replacement in Los Angeles, you’re rarely paying for the part alone. The material might be $30 to $400 depending on whether it’s a linear drain grate, a roll of KERDI fabric, or a full DITRA-HEAT mat. The labor is the real cost. Replacing a failed drain assembly in an existing shower runs $2,360 to $7,670 when we have to remove tile, verify the subfloor, and reinstall. If the failure escalated to subfloor replacement, the number moves toward the $10,620 to $33,040 range of a small bathroom remodel, because we’re rebuilding the waterproofing envelope, not patching it. Every quote from Mason Remodeling Co includes a written line-item price before work starts, and our 365-Day Done Right Promise covers the repair for a full year from completion.
See the difference
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AfterDIY or Call Us?
You can safely do one thing: take photos. Pull back the edge of a loose corner of tile if it’s already moving, photograph the embossed model number on the Schluter membrane or drain flange, and send it to us. What you shouldn’t do is peel up membrane, remove a bonded drain, or cut into KERDI-BOARD to “take a look.” Once the waterproofing layer is compromised, every day of delay moves water further into framing, and in a Los Angeles ADU with wood framing over a garage or crawlspace, that means dry rot and mold. Repairing this is not a weekend project. Call (213) 632-5711 and we’ll send a technician with the name, photo, and ID badge before they arrive, under the Threshold Standard we’ve used since 2004.
FAQs
A properly installed Schluter membrane should last 30+ years, even with Southern California’s temperature swings. What fails in Los Angeles is usually the installation, not the product. Overly thinned thinset, missed spot bonds, or shallow overlaps account for nearly every failure we open up. Call (213) 632-5711 for a free inspection if you suspect one.
A single failed seam or drain flange can often be repaired without a full rebuild, but only if the water damage hasn’t migrated into the subfloor. We cut back the tile to the nearest stable edge, reset the KERDI fabric or drain assembly, and re-tile. If the OSB or plywood underneath is compromised, that section gets replaced before the new membrane goes down, and the cost moves into the bathroom remodel range.
Most single-part replacements, like a KERDI drain grate or a short seam repair, are done in two visits: one to expose and inspect, one to waterproof and re-tile. The full job usually runs three to five days for a shower base repair including tile setting and grout cure, depending on the tile size and whether we’re matching existing material.
Our Los Angeles trucks carry the most common Schluter pieces: KERDI fabric, DITRA mat, 2-inch and 4-inch KERDI-BAND, inside and outside corners, pipe seals, and linear drain grates. If your ADU or addition uses a specialty profile, we order direct and it’s typically in hand within two or three business days. We also stock parts for KraftMaid cabinetry, Cambria and Silestone surfaces, so one call can tell you whether it’s in the truck or on order.
Get a Free Estimate for Your Schluter Repair in Los Angeles
We serve Los Angeles homeowners with Schluter-compatible home additions and ADU repair work that’s priced in writing before a single tool comes off the truck. Know who’s coming, know what it costs, know it’s guaranteed. Everything else is just noise. Call (213) 632-5711 to schedule a free estimate. You’ll get a live person, 24/7, and a written price before any work begins. Isaac Pruett grew up in the San Fernando Valley and has spent two decades running residential and commercial jobs across Los Angeles County, so we’ve seen every Schluter failure this climate can produce. We’ll tell you straight what it takes to fix it.
Written by Isaac Pruett, Owner, Mason Remodeling Co at Mason Remodeling Co Los Angeles, serving Los Angeles and nearby areas.
