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Schluter Home Additions & ADU: The Los Angeles Owner’s Guide
If you’re planning a home addition or ADU with Schluter waterproofing and uncoupling systems, the installed cost in Los Angeles typically runs $53,100 to $153,400 for an addition and $106,200 to $259,600 for a full ADU, depending on square footage, foundation work, and finish level. We stock Schluter profiles, KERDI membrane, DITRA underlayment, and KERDI-BOARD for additions across the city, and our crews install them as part of the build, not as an afterthought. Most owners discover a Schluter product problem during a remodel walkthrough: cracked tile at a transition, water staining under a shower bench, or a profile that’s pulling loose at the edge.
Here’s what you need to know before you call anyone: who is coming, what it costs, and what is backed up. Isaac Pruett grew up in the Sylmar end of the San Fernando Valley, where half the neighborhood spent weekends fixing what the last guy did wrong. He’s spent two decades remodeling homes across Los Angeles, and his rule on Schluter work is simple: if the waterproofing isn’t right, nothing else matters.
Which Schluter Models This Applies To
Schluter makes waterproofing and uncoupling systems, not finished additions themselves. The parts that matter for a home addition or ADU in Los Angeles are KERDI membrane (the orange waterproofing fabric), DITRA and DITRA-HEAT (uncoupling underlayment for tile floors), KERDI-BOARD (waterproof foam backer board), and the metal profiles like SCHIENE, RONDEC, and DECO that finish tile edges and transitions.
The compatibility gotcha most people miss: KERDI and DITRA must be bonded with Schluter’s own thin-set or an approved unmodified mortar. Regular modified thin-set traps moisture against the membrane and voids the warranty. That’s a $30,000 mistake on a shower in a $153,000 addition. We also see owners buy the wrong profile height. SCHIENE comes in 1/4″, 5/16″, 3/8″, 1/2″, and taller, and the profile must match tile thickness plus thin-set depth. Too short leaves a lip that catches toes; too tall leaves a groove that collects grime.
For OEM versus aftermarket: Schluter’s own profile material is aluminum, stainless steel, or PVC, and there is no quality aftermarket equivalent for KERDI membrane. The membrane is the waterproofing. When someone sells a cheaper “KERDI-compatible” sheet, it’s just a piece of plastic that hasn’t been through the same flood testing. We also stock parts for KraftMaid, Cambria, and Silestone projects, but on waterproofing, there’s only one brand that earns its price.
Styles & brands we work with
Signs Your Schluter Home Additions & ADU Is Failing
- Water staining on the ceiling below a second-floor bathroom or addition. This means the KERDI lap seam has failed or was never installed correctly at the floor-to-wall transition. It shows up months after the first shower, not during the build.
- Loose or cracked tile at the edge of a shower curb or niche. The profile wasn’t set in thin-set properly, or the substrate flexed behind it. The cracked grout is a symptom; the movement behind the tile is the problem.
- A musty smell you can’t locate in a new ADU kitchen or bath. Water is getting past the DITRA at a seam and sitting against the subfloor. By the time you smell it, the underlayment bond has been compromised.
- Aluminum profiles that have pulled off the wall or are pitting. Los Angeles tap water is hard, and improperly sealed profiles corrode at the cut ends, especially in showers. A profile that is pulling loose usually means it was installed after the membrane, not before it.
- A visibly buckled DITRA mat under tile in a room that gets direct sun. Southern California heat moves slabs, and if the thin-set was mixed too dry or skinned over before the mat was embedded, the whole floor assembly starts talking to you.
See the difference
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After
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After
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AfterReplacement Cost & What’s Included
For a Schluter system repair inside a Los Angeles home addition or ADU, budget $945 to $2,950 for a profile replacement or isolated membrane patch, and $5,310 to $14,160 for a full shower pan rebuild. When the Schluter work is part of a new addition, it’s baked into the $53,100 to $153,400 range we quoted above.
The parts themselves are not the expensive line item here. A SCHIENE profile runs $25 to $80 depending on length and finish. KERDI membrane is roughly $1.75 to $2.50 per square foot off the shelf. What you are paying for is the tear-out, the prep, the bonding, and the labor of a crew that does waterproofing correctly the first time, because the cost of doing it wrong is removing the tile, the membrane, and starting the whole assembly over.
We deliver a written price before any work starts. That is not optional, not a promotion, and never waived. The written price covers parts, labor, disposal, and the finished assembly. Every completed project is covered by our 365-Day Done Right Promise: if the Schluter work is not right within a year of completion, we make it right at no cost to you. A live person answers our phone around the clock, every day of the year.
DIY or Call Us?
Here’s the honest split. You can safely check whether a profile is loose by pressing on it. You can mark water stains with painter’s tape and watch if they grow. You can read your product labels and confirm whether the original installer used Schluter’s approved thin-set. What you should not do is open up a shower floor in a $153,000 addition and start peeling membrane. Waterproofing is a system, and if you guess wrong about which seam failed, you’ve doubled the repair area.
Schluter work is not dangerous in the way that an electrical panel is, but it is unforgiving. A bad patch leaks for months before you see it. If your addition or ADU shows any sign we listed above, call (803) 680-2547 for a free estimate. We’ll tell you what failed, what it costs, and whether it’s worth fixing now or watching for another season.
FAQs
A properly installed KERDI and DITRA system lasts the life of the tile assembly, which in Los Angeles generally means 25 to 40 years for a shower and 20 to 30 years for a floor in a sun-exposed room. What shortens that lifespan is installer error, not material failure. KERDI membrane does not rot, mold, or break down under normal conditions. The failure points are seams, corners, and pipe penetrations that were not bonded fully. We have opened up 10-year-old Los Angeles ADU showers with KERDI still bright orange and bone dry, and we have opened up 3-year-old showers where a missed seam was growing black mold behind the tile. Call (803) 680-2547 if you want us to inspect yours.
Sometimes. An isolated tear above the waterline, a loose profile, or a small unsealed screw hole can be patched with new KERDI and Schluter’s KERDI-FIX sealant, typically $945 to $2,950 in Los Angeles. A failed seam at a shower floor-to-wall corner is different: the tile in that area has to come out, the seam gets proper overlap with new membrane, and the tile goes back. If the leak has existed long enough to damage the subfloor, you’re into the $5,310 to $14,160 rebuild range. We’ll tell you which situation you have before you spend anything.
A profile replacement or small membrane patch is a one-day job. A shower pan rebuild takes two to three days, most of it drying time between thin-set applications. A full ADU waterproofing install during new construction takes one to two weeks, depending on the number of wet areas and whether KERDI-BOARD is being used for the walls. We’ll put the schedule in the written estimate.
Yes. Our trucks carry SCHIENE, RONDEC, and DECO profiles in the most common heights, KERDI membrane rolls, KERDI-FIX sealant, DITRA and DITRA-HEAT mats, KERDI-BOARD in standard thicknesses, and Schluter corners and pipe collars. If your job needs a less common finish like anodized stainless in a 10-foot length, we order it before we start and you see the line item in your written price. No surprise invoices, no verbal estimates that grow on the final bill.
Written by Isaac Pruett, Owner, Mason Remodeling at Mason Remodeling, serving Los Angeles and nearby areas.
