Free written scope consultation - allowances, timeline, and change-order rules on paper before a single trade is scheduled
Schluter Home Additions & ADU: The Los Angeles Owner’s Guide
Home additions and ADU construction in Los Angeles typically run $53,100 – $153,400 for a finished project, and our crews work with Schluter waterproofing and uncoupling systems throughout the build. Most homeowners call us when they’ve started noticing issues with an existing addition or ADU: water staining at the base of a shower wall, cracking tile at the transition between old and new slab, or dampness creeping through an ADU floor that was poured over concrete. Those symptoms usually trace back to either a failed waterproofing layer or a slab transition that moved when it should not have.
We’re an independent remodeling contractor, not a Schluter affiliate. What that means for you: we install Schluter products because they hold up in Los Angeles soil and climate conditions, and we stock enough Schluter membrane, banding, and profiles on our trucks to keep a job moving. We also give you a written price before any work starts, so if you’re pricing a bathroom in a garage conversion or a full ADU with a kitchenette, you’ll know the number up front.
Which Schluter Models This Applies To
Schluter makes several product lines that show up in home addition and ADU work, and each has its own compatibility rules. The big ones are the Ditra uncoupling membrane (used under tile floors where new slabs meet old ones), Kerdi waterproofing membrane (shower walls, tub surrounds, steam rooms), Kerdi-Board (waterproof wall panels that replace cement board), and Schluter profiles (metal edge trim that finishes tile perimeters, transitions, and stair nosings).
For Ditra, the version matters: standard Ditra works under most tile, but Ditra-XL is spec’d for dimensional stone and large-format tile over plywood. If someone installs standard Ditra where Ditra-XL belongs, the floor can flex and tile cracks along the joint. Same with Kerdi: Kerdi membrane and Kerdi-Band need proper 2-inch overlap to remain waterproof. We see failed ADU showers in Los Angeles where a previous installer butted the seams together and sealed only the surface. That’s a slow leak that rots the curb for a year before it shows up as staining on the other side.
OEM Schluter materials are always our default for waterproofing work. The warranty system only stays intact when the full Schluter assembly is used the way their technical drawings specify. We also install KraftMaid, Cambria, and Silestone products in these projects, but waterproofing stays Schluter because the compatibility and the manufacturer’s testing are what protect the structure.
Styles & brands we work with
Signs Your Schluter Home Additions & ADU Is Failing
- Tile cracks running in a straight line across the floor. The most common cause in Los Angeles additions is slab movement at the transition between old foundation and new. If uncoupling membrane was skipped or installed wrong, the crack telegraphs through the tile.
- Grout turning dark or staying damp near the shower base. Water is wicking through the waterproofing layer. Kerdi seams that were overlapped incorrectly or punctured during tile setting will let moisture reach the substrate and never fully dry.
- Musty smell in an ADU that won’t go away. This usually means water is trapped between the waterproofing and the framing. In Los Angeles’s dry climate, that smell is a stronger signal than visible mold because the air is dry enough to hide moisture damage until it’s advanced.
- Schluter profile edges lifting or separating from the tile. The profile was either adhered with the wrong material or the thinset under the tile edge wasn’t fully pressed. Water gets under the edge, and the corner starts to peel.
- Hollow sound when you tap the shower floor. Thinset didn’t bond between the Kerdi layer and the tile, or between the Ditra and the subfloor. The void lets tile flex, and flex becomes crack.
See the difference
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After
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AfterReplacement Cost & What’s Included
Full home addition projects in Los Angeles run $53,100 – $153,400 depending on square footage, whether you’re adding a bathroom or kitchen, and what the foundation requires. ADU construction runs $106,200 – $259,600 when it’s a full detached or attached unit. For Schluter-specific repair work inside an existing addition, scope is smaller but still meaningful: a failed shower pan membrane replacement with new Schluter Kerdi and tile typically lands between $5,310 – $14,160. A Ditra replacement under a failing kitchen floor with large-format tile runs $3,540 – $11,800, depending on tile size and whether cabinets need to be pulled.
Every written price we hand you includes the Schluter materials, thinset, labor, clean-up, the photo of the finished work before the crew leaves, and the 365-Day Done Right Promise. If it’s not done right, we make it right. We don’t write estimates that grow once the crew arrives. The number on the paper is the number.
DIY or Call Us?
You can check a few things without opening the wall: tap the shower floor for hollow spots, look for straight-line tile cracks, and run your hand along the tile where the floor meets the wall to feel for any flex or lip. Those checks tell you whether you likely have a Schluter membrane failure or a simpler surface issue.
What you should not do is peel back tile to inspect for yourself. Once the waterproofing layer is compromised, every day of exposure lets more moisture into the framing. Los Angeles soil moves, especially in hillside neighborhoods with expansive clay, and the fix almost always involves removing tile, assessing the membrane, and rebuilding the assembly to Schluter’s spec. That’s skilled work. One wrong seam in a Kerdi shower pan means tearing it out again in two years. If your checks turn up anything that looks like water or movement, call us at (949) 850-9896 and we’ll come look at it and give you a written scope before anything gets touched.
FAQs
A properly installed Schluter Kerdi or Ditra assembly should last the life of the tile installation, which in a Los Angeles home addition or ADU typically means 20 to 30 years or longer before tile replacement. Early failure almost always traces back to installation error, not product defect. Call us at (949) 850-9896 if you’re seeing signs of water before the 10-year mark; that’s not normal.
No. Once a Kerdi seam has leaked or a Ditra mat has pulled loose, patching the surface does not restore the assembly. The waterproofing layer needs to be removed in the affected area and redone with proper overlap and embedded thinset. A patch over a failed seam is still a path for water. Graham will tell you that on a walkthrough: the fix is always replacement of the affected section, never a surface coating.
Most Schluter shower pan replacements inside a Los Angeles home addition take 3 to 5 working days from tear-out to grouted tile, with a day of cure time before use. A Ditra floor replacement under a kitchen typically runs 2 to 4 days depending on cabinet work. We sequence quiet work around your kids’ sleep and school hours where possible.
We stock standard Schluter Kerdi membrane, Kerdi-Band, Kerdi-Board, Ditra, and the common profile sizes on our trucks, so most repair work starts same-week. Special profile finishes or non-standard widths may be ordered, which adds a few days. We’ll tell you which category your project is in before the written price.
When you’re ready to price the fix, call us at (949) 850-9896. A live person answers, and we’ll get your project scoped and priced in writing before any work starts.
Written by Graham Stein, Owner, Elmstead Remodeling at Elmstead Remodeling, serving Los Angeles and nearby areas.
