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Schluter Home Additions & ADU: The West Covina Owner’s Guide
When your Schluter home addition or ADU build in West Covina runs into trouble, you’re usually staring at one of two things: waterproofing that failed at a seam, or substrate that shifted under temperature swings. We stock the Schluter profiles, KERDI membranes, and DITRA uncoupling mats needed to fix both, and a full Schluter-spec addition or ADU in West Covina typically runs $45,000 to $130,000 installed, depending on square footage and finishes. Most owners discover the problem the same way: a hairline crack in the tile over a DITRA seam, or damp drywall where a KERDI overlap was never properly embedded. You don’t need a full tear-out. In a lot of cases, the right Schluter part and a day of skilled work gets you back to watertight.
Which Schluter Models This Applies To
Schluter’s home addition and ADU systems are built around a handful of core products: KERDI waterproofing membrane, KERDI-BOARD for walls and ceilings, DITRA and DITRA-HEAT uncoupling mats for floors, SCHLUTER profiles for edge trim and transitions, and KERDI-FIX sealant as the adhesive caulk. The compatibility gotcha most West Covina homeowners hit is this: KERDI membrane only bonds correctly to unmodified thin-set mortar (or Schluter’s ALL-SET). Grab a modified mortar off the shelf and the latex can’t dry behind the impermeable membrane, which means it never cures. We see that failure regularly in garage conversions off Amar Road, where a weekend DIYer used the wrong bag and now the tile is hollow. For identification, every Schluter profile has a model code stamped on the visible flange – look for things like “Jolly,” “Schiene,” or “RONDEC” followed by a size in millimeters. That code tells us the exact metal thickness and finish so the replacement matches what’s already on your tile edges.
On OEM versus aftermarket: Schluter’s products are patented systems, and the membranes don’t have true aftermarket equivalents. Generic orange sheet membranes exist, but they don’t carry the same ICC-ES evaluation reports that West Covina building inspectors accept. For profiles, we do stock quality aluminum and stainless options from other manufacturers when a homeowner wants a different finish, but if your walls are already waterproofed with KERDI, we recommend staying in the Schluter family so the warranty chain stays intact. Sawyer Remodel West Covina is an independent contractor, not a Schluter dealer, which means we quote honestly about when OEM matters and when a solid alternative does the job.
Styles & brands we work with
Signs Your Schluter Home Additions & ADU Is Failing
- Tile cracked directly over a DITRA seam. The uncoupling mat did its job for a while, but if the subfloor flexed beyond spec, stress concentrates at the seam and the tile above takes the hit. The mat may still be fine – the issue is usually inadequate thin-set coverage underneath.
- Damp drywall or baseboard swelling at the floor line. Water is wicking up behind a KERDI overlap that wasn’t embedded with a full 2 inches of mortar. The water is getting behind the membrane and traveling.
- Loose or lifting tile at a transition. Schluter profiles like Schiene or Reno-TX are mechanically anchored under the tile edge. If the profile’s perforated leg wasn’t fully bedded, the metal flexes and the tile pops loose.
- Musty smell in an ADU bathroom with no visible leak. Water is pooling between the membrane and the substrate. It’ll rot the framing before you ever see a drip on the ceiling below.
- Grout cracking in straight lines running wall-to-wall. That’s not a grout problem. That’s a floor deflection problem, and it usually means the DITRA was installed over plywood that doesn’t meet the L/360 span standard West Covina inspectors expect.
See the difference
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After
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AfterReplacement Cost & What’s Included
A Schluter-spec home addition in West Covina runs $45,000 to $130,000, and a full ADU construction runs $90,000 to $220,000. If you’re fixing a failed Schluter component rather than building new, the math changes: a KERDI seam repair on an existing shower typically runs $900 to $2,500 depending on how much tile has to come out. Replacing a section of DITRA under a cracked tile floor runs $1,200 to $3,800. And new Schluter profiles along a tile edge sit between $200 and $800 including labor. Every quote we write in West Covina is line-item: parts, labor, disposal, and the permit fee if the city requires one for your scope. The price we hand you is the price you pay. No change orders unless you change the plan. Our 365-Day Done Right Promise covers the workmanship on every Schluter repair, and if it fails within a year, the second visit is free, full stop.
DIY or Call Us?
You can safely pull a loose profile cap and re-snap it yourself if the anchoring leg is still solid. You can also check whether your KERDI seams show the required 2-inch minimum overlap. That’s where DIY should end. Schluter waterproofing is a system – one wrong mortar choice, one seam pressed without full embedment, and the failure stays invisible until the framing rots. Good work shows. Bad work shows up later. If you’re already seeing cracked tile, damp drywall, or a musty ADU, the membrane is compromised and you need someone who installs Schluter every month, not a weekend guess. Call Luca Romano and our crew at (341) 217-4204 for a free estimate. We’ll tell you what failed, why it failed, and exactly what it costs to fix before we pick up a tool.
FAQs
A properly installed Schluter KERDI system lasts 30 to 50 years – the membrane itself doesn’t degrade, but the thin-set bond can fail over time if the substrate moves or was installed wrong. In West Covina, where summer heat pushes 100°F and winter nights drop into the 40s, expansion and contraction stress those seams more than in coastal climates. Call (341) 217-4204 and we’ll inspect your existing Schluter install for free.
In most cases, a failed seam can be repaired by removing the affected tile, cutting back the old membrane, and installing a new KERDI patch with proper 2-inch overlap and KERDI-FIX at the edges. If the substrate behind the membrane is rotted or the failure covers more than a few square feet, a larger replacement makes more sense. Get an exact answer with a free estimate from Sawyer Remodel West Covina.
A single seam repair or DITRA patch typically takes one day of demo and install, plus 24 to 48 hours of mortar cure time before tile goes back up. Most West Covina jobs we schedule are completed within three to four days from start to grouted tile. Call (341) 217-4204 for a timeline on your specific failure.
We stock the most common Schluter profiles (Jolly, Schiene, RONDEC in standard finishes), KERDI membrane, KERDI-BAND, KERDI-FIX, and DITRA mat on our trucks for West Covina service calls. Less common profiles and specialty sizes we order direct from Schluter with a two-to-four-day lead time. We’ll tell you before scheduling which bucket your repair falls into.
Written by Luca Romano, Owner, Sawyer Remodel West Covina at Sawyer Remodel West Covina, serving West Covina and nearby areas.
