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Schluter Home Additions & ADU: The San Francisco Owner’s Guide
Schluter waterproofing and uncoupling membrane products integrated into a home addition or ADU typically run between $53,100 and $153,400 installed in San Francisco, depending on square footage, foundation work, and how much of the wet area needs KERDI membrane coverage. Most owners discover a Schluter failure the same way: a soft spot in the tile floor outside a shower, efflorescence blooming along a curb line, or a musty smell that never quite goes away even after the dehumidifier runs all weekend.
We stock Schluter KERDI-BOARD, KERDI membrane, DITRA underlayment, and prefabricated KERDI-SHOWER trays and curbs on our trucks alongside fixtures from Kohler, Moen, and Grohe. If your ADU or addition was built with Schluter systems and water is getting where it should not, we can identify the failed component, open the affected area cleanly, and replace the membrane or board so the tile assembly stays waterproof for the life of the room. Elmstead Remodeling San Francisco is an independent contractor, not a Schluter affiliate, but Graham Stein and our crews have installed and repaired Schluter systems in homes throughout San Francisco for years, from the Sunset District to jobs within walking distance of Dolores Park.
Key Takeaways:
- Schluter home addition and ADU work in San Francisco runs $53,100 to $153,400 depending on scope, access, and the extent of membrane repair or replacement
- KERDI and DITRA failures are usually traceable to installer error at seams and corners, not product defects
- We carry Schluter membranes, boards, trays, and curbs on the truck for faster diagnosis and repair
- Written price before any work starts, with shoe covers and drop cloths on every visit
Which Schluter Models This Applies To
Schluter’s product line for additions and ADUs covers KERDI waterproofing membrane, KERDI-BOARD building panels, DITRA and DITRA-HEAT uncoupling underlayments, KERDI-SHOWER trays and curbs, KERDI-LINE and KERDI-DRAIN drainage assemblies, and KERDI-BAND for seams and transitions. Most wet-area failures we see in San Francisco additions involve seams where KERDI-BAND was lapped too short, corners where membrane was not pressed firmly into thinset, or dabs of sealant that missed a fastener penetration in KERDI-BOARD.
Identification matters before any work begins. If you still have the original permit docs or a tile contractor’s invoice, the Schluter product name will usually be listed. If not, our crew can verify what was used by opening a small access point behind an escutcheon plate or at a curb edge, then matching the replacement membrane or board to the existing assembly. OEM Schluter components are really the only sensible repair path here; aftermarket roll-on liquid membranes or generic foam boards do not lock into the Schluter system the same way, and the manufacturer’s warranty becomes pointless when you mix systems. If you are planning a new ADU or addition, we specify Schluter from the start and write every part name into the project scope before the first day of framing.
Styles & brands we work with
Signs Your Schluter Home Addition Is Failing
- Efflorescence or mineral staining along shower curbs and wall junctions. Water is wicking through a seam or a pinhole breach in the membrane, carrying dissolved minerals from the mortar bed to the surface. The membrane is no longer a continuous barrier.
- Soft or hollow-sounding floor tile outside the wet zone. In an ADU bathroom, this usually means water has migrated beyond the shower footprint through an improperly lapped KERDI seam or a failed DITRA edge. The tile may be fine; the substrate under it is not.
- Musty odor that returns within hours of drying the room. Trapped moisture inside the wall cavity or under the tile assembly is feeding mold growth. Paint and caulk fixes will not solve it because the moisture source is behind the finish surface.
- Loose tile at floor-to-wall transitions. Schluter assemblies depend on KERDI-BAND creating a continuous plane from floor to wall. If that band was embedded with dry thinset or insufficient overlap, the bond fails first at the exact place water pools most.
- Baseboards swelling or paint bubbling near a curbless shower. A curbless Schluter shower has a very shallow slope tolerance. If the tray or mud bed was set slightly off-level, water runs toward the vanity wall instead of the KERDI-LINE drain, and the first visible evidence is baseboard damage.
Replacement Cost & What’s Included
San Francisco home additions and ADUs using Schluter waterproofing systems fall in a $53,100 to $153,400 installed range. The spread depends on project size, how much foundation or structural work is required, whether we are building new wet walls and floors from framing or repairing an existing Schluter installation, and local factors like daylighting requirements, soil conditions, and access for materials delivery. Smaller scopes that involve one bathroom plus a modest living area sit at the lower end; a full second-story addition or a detached ADU with a complete kitchen and two baths sits at the upper end.
Every price we write includes the Schluter membrane, board, tray, and drain components at their named-brand cost, all mortar and fasteners, waterproofing labor with proper cure times between steps, and a detailed line-item breakdown so you can see exactly what each part costs. There are no change orders that appear after the crew arrives. The 365-Day Done Right Promise covers the completed work; if a seam fails or a tray shifts after the job is done, we come back and make it right.
| Scope Component | San Francisco Installed Range |
|---|---|
| Full home addition with Schluter wet areas | $53,100 – $153,400 |
| ADU construction with Schluter waterproofing | $106,200 – $259,600 |
| Garage conversion with Schluter bathroom/kitchen | $35,400 – $94,400 |
| Schluter membrane repair inside existing addition | $3,540 – $10,030 (tile removal, membrane replacement, re-tile, grout) |
| Walk-in shower replacement with KERDI system | $5,310 – $14,160 |
See the difference
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AfterDIY or Call Us?
A homeowner can safely do two things: note exactly where the tile is soft, stained, or loose, and photograph the area before calling us. That record helps our crew pinpoint the likely membrane breach without opening more wall than necessary. What is not safe is pulling tile and attempting a Schluter membrane repair without knowing how the original installer laid the system. KERDI membrane joints require a specific thinset type, a minimum lap width, and immediate embedding in wet mortar; KERDI-BOARD fasteners must be sealed at each penetration. A missed seam or a wrong trowel notch means the new membrane fails silently behind new tile, and you have paid for a second repair inside a year. Water intrusion inside an ADU wall cavity also carries electrical risk if outlets or switches sit in the affected stud bay. If the area is wet and you can see staining around an outlet, shut the breaker for that circuit and call us at (831) 480-4497. Graham Stein will walk the job himself, identify the failed component, and give you a written price before any tool touches the floor.
FAQs
A correctly installed Schluter KERDI or DITRA assembly should last the life of the tile assembly, typically 25 to 50 years, because the membrane itself does not degrade under ordinary conditions; what fails in San Francisco is almost always the installation at seams, corners, and fastener points. Call (831) 480-4497 and we can inspect the membrane access points and tell you whether the failure is localized or systemic.
Yes, in many cases we can remove a targeted section of tile, patch in a new KERDI membrane or KERDI-BAND with the proper overlap, and re-tile only the affected area, but only if the original substrate is still sound; if water has saturated the mortar bed or wall board, the repair zone grows. A free estimate will tell you which situation you have before any demolition begins.
A membrane repair inside an existing shower or bathroom typically takes three to five working days including thinset cure times between steps, while a new ADU or home addition with Schluter systems runs eight to sixteen weeks depending on scope and permitting. We set quiet hours during the workday and send a photo of the clean-up before the crew leaves each day.
Our trucks carry the Schluter components we use most often in San Francisco: KERDI membrane rolls, KERDI-BAND, inside and outside corners, KERDI-BOARD in common thicknesses, DITRA sheets, and KERDI-SHOWER trays and curbs in standard sizes; unusual drain placements or custom tray dimensions may require a short-order pickup from a local Schluter distributor. Either way, the written price you receive includes all parts, and we do not start a job until the correct components are on-site.
Get Your Schluter Home Addition or ADU Priced in Writing
If your Schluter waterproofing is showing signs of failure, or if you are planning an addition or ADU in San Francisco and want KERDI and DITRA systems specified from the start, call (831) 480-4497. Graham Stein will walk the space with you, name the exact Schluter products the project needs, and hand you a written price before any work begins. We are also happy to discuss cabinetry from KraftMaid, countertops from Cambria or Silestone, and fixtures from Kohler, Moen, or Grohe if your addition includes a kitchen or bath. Shoe covers go on at the door, drop cloths go down before any material moves, and the clean-up photo is sent before the crew leaves. Tell me what the room needs to do, and we’ll figure out the rest from there.
Written by Graham Stein, Owner, Elmstead Remodeling San Francisco at Elmstead Remodeling San Francisco, serving San Francisco and nearby areas.
