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Schluter Home Additions & ADU: The Los Angeles Owner’s Guide
A Schluter home addition or ADU in Los Angeles typically runs $53,100 to $153,400 installed, depending on square footage, foundation work, and the Schluter waterproofing systems you spec. We stock Schluter KERDI-BOARD, DITRA, and KERDI waterproofing membrane on our trucks for additions and ADU projects across LA, and most material orders land within 3 to 5 business days. The call usually starts the same way: “We started opening the wall and found water damage behind the old shower pan,” or “Our ADU floor is spongy near the bathroom.” Schluter parts don’t fail quietly, and by the time you notice, you’re usually looking at a remodel-scale fix, not a caulk-and-paint patch.
Key Takeaways:
- Installed Schluter home additions and ADUs in Los Angeles: $53,100 – $153,400
- We’re an independent installer, not a Schluter affiliate, which means we recommend what fits your build, not what moves inventory
- The part most owners discover failing first is the waterproofing layer behind tile, usually because it was installed wrong years ago
- Every estimate includes a written price before work starts, per The Relay Visibility Guarantee
- Call (254) 272-5876 for a free estimate on your addition or ADU
Which Schluter Models This Applies To
Schluter’s home addition and ADU relevance splits across three product families: KERDI (waterproofing membrane for showers, tub surrounds, and wet walls), DITRA (uncoupling underlayment for tile floors), and KERDI-BOARD (foam backer board for walls and curbs). If your ADU or addition was built in the last 15 years and uses tile anywhere, odds are high one of these systems is in the wall or under the floor. The gotcha most LA owners run into: older Schluter installs used DITRA matting that was not paired with a compatible modified thinset below or above the membrane. Over time, that bond fails and tiles start cracking or lifting.
OEM vs aftermarket: For Schluter waterproofing, we recommend OEM. The KERDI membrane’s fleece backing is engineered to bond with Schluter’s thinset chemistry, and the company’s warranty only holds if the full system is Schluter. Generic polyethylene sheet membranes can work in a pinch, but LA’s moisture swings between coastal fog and dry heat punish shortcuts. When you’re already spending $50,000+ on an addition, saving $400 on off-brand waterproofing is a bad trade. For edge trim and curb profiles, quality aftermarket equivalents from Schluter-licensed fabricators are fine if they match the gauge and finish of your existing trim.
How to identify what’s in your wall: pull a tile, or remove a fixture escutcheon plate, and look for orange fleece-backed sheeting (KERDI) or orange matting with a grid pattern (DITRA). If you see painted-on waterproofing instead, that’s not Schluter, and the failure you’re chasing may be a different animal.
Styles & brands we work with
Signs Your Schluter Home Additions & ADU Is Failing
- Grout cracking along shower floors or wall transitions within a few years of install. The substrate behind the tile is moving or the waterproofing layer has delaminated. In LA’s clay soil, slab movement transfers through DITRA if the matting wasn’t installed over a properly prepared subfloor.
- Musty smell near the ADU bathroom or kitchen that you can’t eliminate. Water is trapped behind tile where the waterproofing failed. Schluter systems are designed to let moisture escape, but a failed seam or missing corner joint traps water against studs.
- Staining or paint bubbling on the wall behind a tiled shower or along a curb. That’s evidence water has already migrated past the waterproofing plane. By the time the paint fails, framing damage is almost certain.
- Loose or hollow-sounding tiles in the addition’s floor. If you tap a tile and hear a hollow thunk, the thinset bond to the DITRA matting is gone. This is the classic sign of an unmodified/modified thinset mismatch at original install.
- Cracking in the addition’s slab or foundation that telegraphs into tile. Schluter DITRA is designed to uncouple from substrate movement, but it can’t compensate for actual foundation settlement. If cracks run through the tile in straight lines, the issue may be structural, not Schluter-related.
See the difference
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After
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After
Before
AfterReplacement Cost & What’s Included
For a standalone Schluter shower waterproofing correction within a larger addition, expect $2,360 to $7,670, which includes demo to the studs, new KERDI membrane, seam banding, corner pieces, and re-tile. A full bathroom in an ADU using Schluter waterproofing runs $10,620 to $33,040. A full home addition with Schluter systems integrated lands in the $53,100 to $153,400 range depending on whether you’re building a bump-out, a garage-to-living conversion, or a ground-up ADU shell. The biggest cost variables in Los Angeles are foundation type (post-tension slab vs raised), seismic shear requirements, and whether the soil will require extra piering or grading.
Every quote we give includes the parts, labor, debris hauling, and a written line-item price before any work starts. We pull permits and schedule inspections where required, and the workmanship is covered under our 365-Day Done Right Promise: if it’s not done right, we make it right. That’s not a verbal promise. It’s written into every contract.
DIY or Call Us?
You can safely diagnose a lot of Schluter failures: pull a vent cover and inspect for orange fleece, tap tiles for hollowness, run a moisture meter on the wall behind the shower. What you shouldn’t do is tear out a shower wall or floor in an ADU or addition and attempt to re-waterproof it yourself. The moment you open a wall that separates living space from studs and framing, you’re dealing with California building code, possible mold remediation, and waterproofing seams that fail inside 6 months if not lapped, mortared, and banded correctly. We’ve torn out more DIY attempts in Silver Lake and Echo Park than we can count, and they always cost more than if the original call had gone to a pro. If you want eyes on it first, call (254) 272-5876. We’ll send a background-checked technician with a written price for the repair before anything gets demoed.
FAQs
A properly installed Schluter KERDI or DITRA system should last the life of the tile assembly, 30 years or more. The weak point is always the install: a bad seam, a missing corner piece, or the wrong thinset will fail inside a few years, not decades. In Los Angeles, the biggest environmental strain is the Santa Ana dry-heat cycle followed by coastal moisture, which causes expansion and contraction at tile transitions. Call (254) 272-5876 if your tile is cracking sooner than it should.
If the failure is localized to a seam or corner, we can sometimes do a targeted repair without a full tear-out. But once water has migrated past the membrane and into the studs, the only correct fix is demo to the framing, dry-out, and re-waterproofing from scratch. We’ll tell you which one you’re looking at after a site inspection, and we put that recommendation in writing before you spend anything.
A standalone ADU on a prepared foundation runs 4 to 6 months from permit approval to final inspection in Los Angeles. A shower waterproofing correction within an existing addition runs 1 to 2 weeks. We’ll give you a schedule with your written price, and you’ll get photo updates before and after key milestones through The Relay Visibility Guarantee.
We stock KERDI membrane rolls, DITRA matting, Schluter corner pieces, and KERDI-BOARD panels at our shop and keep them on the truck for most Los Angeles jobs. Specialty curb profiles, drain grates, and edge trim in specific finishes are ordered direct from Schluter’s distribution and typically arrive within a week. You never need to source anything yourself unless you want a very specific finish we don’t carry.
Written by Luca Romano, Owner, Sawyer Remodeling at Sawyer Remodeling, serving Los Angeles and nearby areas.
