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Schluter Home Additions & ADU: The Long Beach Owner’s Guide
Most Long Beach homeowners hit this page because a Schluter waterproofing detail failed inside a home addition or ADU, or because they’re planning one and want the waterproofing system spec’d right from the start. A full Schluter-equipped home addition in Long Beach typically runs $45,000 to $130,000, while an ADU with Schluter waterproofing generally lands between $90,000 and $220,000. The failed part is usually not the Schluter membrane itself. It’s almost always the seam, the drain assembly, or a substrate that moved underneath it.
We’re Sawyer Remodel Long Beach, an independent general contractor, not a Schluter affiliate or distributor. What we are is a crew that has pulled apart enough failed Schluter details in Long Beach bathrooms, kitchens, and granny flats to know exactly what goes wrong first. Luca Romano, our owner, learned framing and finish work at Los Angeles Trade-Technical College and has spent the better part of two decades cutting into walls across this city, from Belmont Shore bungalows to ADUs near the Queen Mary. The work tells you everything. The rest is just talking.
Which Schluter Models This Applies To
Most failed Schluter parts we see in Long Beach home additions and ADUs fall into three categories: KERDI membrane seams and corners, KERDI-DRAIN assemblies, and DITRA underlayment edges where they meet door thresholds or transitions. The compatibility gotcha is that KERDI and DITRA are not interchangeable. KERDI is a polyethylene waterproofing membrane for walls and shower pans. DITRA is a polypropylene uncoupling mat for floors. If someone used DITRA on a shower wall, it leaks. We see that mistake at least once a quarter.
Identifying your exact Schluter part means reading the printed grid on the back of the membrane or the stamp on the drain collar. The membrane thickness matters: KERDI comes in 4-mil, 8-mil, and 10-mil weights. DITRA is 1/8 inch thick, DITRA-XL is 5/16 inch. The OEM-versus-aftermarket decision here is different than it is for cabinet hardware or trim. Schluter’s warranty only applies when the entire system is Schluter, including the thinset and the band. Mixing an aftermarket drain with KERDI voids the system warranty, even if the aftermarket part is physically compatible. For a $45,000 addition or a $120,000 ADU, that’s not a risk worth taking. We stock genuine Schluter KERDI, KERDI-BAND, KERDI-DRAIN, and DITRA on our trucks, plus matching Schluter thinset.
Styles & brands we work with
Signs Your Schluter Home Additions & ADU Is Failing
- Water staining on the ceiling below a second-story bathroom. In a Long Beach ADU with a shower on the ground floor, you’ll see it as discoloration on the baseboard or flooring outside the shower. The cause is almost always a KERDI seam that wasn’t lapped with KERDI-BAND, or a seam that pulled apart when the framing settled.
- Musty smell that won’t leave, even with the window open. Schluter membranes don’t rot or mold themselves. The smell is the wood behind them. A pinhole in a seam lets moisture wick into the studs, and Coastal Long Beach humidity keeps it damp long after the shower dries.
- Loose tiles in a shower, especially at the curb or the bottom row. When water gets behind KERDI, it breaks the thinset bond. The tile doesn’t fall immediately, but pressing on it gives a hollow, slightly springy feel. By the time it moves, the pan has been leaking for months.
- Cracked grout at the floor-to-wall transition in a newly built ADU. Long Beach sits close enough to the water that soil can shift slightly from year to year. DITRA is designed to handle that on floors, but only if the edges are properly terminated. A crack at the threshold usually means the underlayment was cut short or the substrate wasn’t flat before the mat went down.
- Water pooling at the base of a curbless shower in a home addition. KERDI-DRAIN needs a specific slope: 1/4 inch per foot in the mortar bed. When a sloped bed is off by even a little, water sits near the drain edge instead of traveling into it. That standing water works into the seam between the membrane and the drain collar over time.
Replacement Cost & What’s Included
Here’s what Long Beach homeowners should expect to pay when we repair a failed Schluter detail or waterproof a new addition or ADU correctly the first time.
| Scope | Installed Price Range in Long Beach |
|---|---|
| Full Schluter waterproofing system (materials only, for a shower) | $800 – $2,500 |
| Schluter repair: tear out, re-waterproof, re-tile | $3,000 – $8,500 |
| Home addition (full build, Schluter included) | $45,000 – $130,000 |
| ADU construction (Schluter waterproofing throughout) | $90,000 – $220,000 |
| Garage conversion with Schluter bathroom | $30,000 – $80,000 |
The range depends on whether we’re repairing a failed membrane or waterproofing from scratch, the square footage of the wet areas, and whether the substrate underneath is still sound. If Long Beach moisture has rotted the framing behind the old KERDI, the framing repair adds cost. Every quote we write is a fixed price in writing before work starts, so the invoice number is the number you approved. The 365-Day Done Right Promise covers the repair for a full year. If it’s not done right, we make it right.
See the difference
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AfterDIY or Call Us?
There is no dangerous high-tension component here like a garage door spring, but Schluter work done wrong is a slow, expensive failure. An owner can safely check for visible gaps at KERDI seams, test for loose tiles, and look for water staining. What an owner should not do is pull up tile and try to patch a KERDI seam. Thinset has to come off cleanly, the substrate has to be bone dry, and a patch over a wet seam just traps the water inside the wall. We’ve opened walls on Long Beach ADUs where a homeowner patched a leak three times, and the repair cost quadrupled because rot had spread behind the membrane. If you suspect a failed Schluter detail, call (562) 512-6480 for a free estimate. We’ll tell you what failed, what it costs, and whether it can be saved.
FAQs
A correctly installed Schluter system should last the life of the tile assembly, which is 30 to 50 years in a typical Long Beach home. Coastal humidity doesn’t degrade the membrane itself. What shortens the lifespan is installer error, typically poor seam lapping or substrate that wasn’t flat before the membrane went down.
Sometimes, if the leak was caught very early and the framing behind the membrane is dry. The damaged section is cut out, the edges are lapped with KERDI-BAND, and the area is patched with new KERDI before retiling. If the framing has rotted, a partial repair won’t hold. Call (562) 512-6480 and we’ll assess it honestly.
A straight seam repair with retiling typically takes 2 to 3 days, including thinset cure time. Full tear-out and re-waterproofing of a shower takes 4 to 6 days. We schedule the work around your calendar and send photo updates before and after, so you know exactly what’s happening without being on site.
We stock genuine Schluter KERDI, KERDI-BAND, KERDI-DRAIN assemblies, DITRA matting, and matching Schluter thinset on our trucks. We also work with KraftMaid and Cambria materials on larger addition and ADU projects, but Schluter waterproofing is always genuine Schluter, never an aftermarket substitute. Call (562) 512-6480 for an exact quote, estimates are free.
No. Our written price is fixed before a single tool is picked up. If we open a wall and find rotted framing, we document it with photos and give you a separate written price for the added scope before we touch it. You approve the number, or we stop. No surprises at the invoice.
Call Sawyer Remodel Long Beach
If your Schluter waterproofing has failed, or you’re planning a home addition or ADU in Long Beach and want the wet areas done right the first time, call (562) 512-6480. We’ll schedule a free estimate, explain exactly what’s wrong or what’s needed, and put the price in writing before any work begins. No contractor who disappears mid-job, no invoice surprises, no voicemail loops. Just a live person, a written price, and a waterproofing system that keeps Long Beach water where it belongs.
Written by Luca Romano, Owner, Sawyer Remodel Long Beach at Sawyer Remodel Long Beach, serving Long Beach and nearby areas.
