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Schluter Home Additions & ADU: The San Antonio Owner’s Guide
If you’re planning a home addition or ADU in San Antonio and want Schluter waterproofing and uncoupling systems specified into the build, we stock and install the full Schluter line, including Kerdi-Board, Kerdi membrane, Ditra, and matching profiles. A Schluter-spec home addition in San Antonio typically runs $45,000 to $130,000 installed, depending on square footage, foundation work, and whether we’re tying into existing plumbing. Most owners call us after they’ve had a failed waterproofing inspection, or after a previous contractor left Schluter seams unbonded and the tile started telegraphing cracks within the first year.
The part itself rarely “fails” in the way a motor or a spring fails. What fails is the installation. In San Antonio’s clay-heavy soil, slab movement is constant, and that’s exactly the condition Schluter’s uncoupling membranes are designed to absorb. When the substrate shifts and a crack appears through the tile six months after move-in, the Schluter layer wasn’t the problem: it was either set with the wrong thinset, or the seams weren’t bonded with Kerdi-Band, or the membrane was installed over an unleveled subfloor. We fix that correctly, and we do it on additions where the rest of the build will be inspected and permitted.
Which Schluter Models This Applies To
We work with the full Schluter Systems catalog, but these are the pieces most Home Additions & ADU projects in San Antonio actually spec:
- Kerdi-Board – waterproof building panel used for shower walls, tub surrounds, and wet-room construction. Comes in thicknesses from 3/8″ to 2″. The compatibility gotcha: not every thinset bonds to Kerdi-Board’s fleece facing. Schluter requires unmodified thinset between Kerdi and tile in most assemblies, but over Kerdi-Board, many setters in San Antonio still use modified and then wonder why the tile tents.
- Ditra and Ditra-XL – uncoupling membranes for floor tile. Ditra is 1/8″ thick; Ditra-XL is 5/16″ and used when you need to match up to 3/4″ hardwood or when you want to pair with Schluter’s heating cables. If your addition has wide-open floor spans and the framing is new, Ditra-XL is usually the right call because new wood moves more in the first two years.
- Kerdi membrane and Kerdi-Band – the waterproofing fabric and seam tape. Kerdi-Band is 5″ wide with a 2″ overlap requirement on every seam. We see a lot of re-work where a previous installer ran Kerdi-Band with only a half-inch overlap and relied on thinset squeeze-out to hold it. It won’t hold under San Antonio’s summer heat.
- Schluter profiles (strips) – the metal trims that seal the edge where tile meets flooring, drywall, or a transition. These are alloy-specific: aluminum profiles move at a different rate than stainless or brass. In a San Antonio south-facing room behind glass, we recommend stainless or aluminum with an anodized finish rather than raw brass, which will patina unevenly within a season.
When you call, our estimator will ask for the product name printed on the edge of the Schluter material (usually stamped like DITRA-1/8 or KERDI-BOARD 1/2), the date of original installation if you know it, and photos of any cracked grout or loose tile. That gets us to the right fix before we ever put a crew on your street.
Styles & brands we work with
Signs Your Schluter Home Additions & ADU Is Failing
- Cracked tile over a new slab – This is the classic San Antonio failure. Clay soil expands in wet years and contracts during drought. Uncoupling membranes exist to isolate that movement. If tile is cracking above a Schluter installation, the membrane was likely bonded with modified thinset, which doesn’t cure properly between non-porous surfaces.
- Water staining on the ceiling below a wet area – Kerdi seams only waterproof when they’re overlapped correctly and pressed flat without folded corners. A quarter-inch fold at the inside of a shower curb lets water through slowly, until the day it doesn’t.
- Mold smell in the addition that won’t clear – Not always Schluter-specific, but when Kerdi-Board is installed backward (fleece facing out is correct, smooth side out is not), water wicks and mold colonizes behind the board where you can’t see it.
- Grout crumbling along membrane seams – Movement telegraphs through the tile assembly at the weakest point, which is almost always a seam. Crumbling grout in a straight line that matches a Kerdi-Band edge is a installation failure, not a grout problem.
- Loose tiles that sound hollow when tapped – This means the thinset mortar skinned over before the tile was set, or the membrane was installed while the thinset under it was already too dry. In San Antonio’s summer, we work in smaller batches precisely for this reason: a 100-degree day will flash-set open thinset in twenty minutes or less.
See the difference
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AfterReplacement Cost & What’s Included
For a Home Additions & ADU project where Schluter materials are failing and need to be stripped and re-done, you’re looking at $45,000 to $130,000 for the full build in San Antonio, depending on scope. If the scope is limited to a wet area inside an existing addition, expect $4,500 to $12,000 for a walk-in shower rebuild including new Schluter Kerdi waterproofing, and $3,000 to $8,500 for a shower replacement where the Schluter layer is intact and only the tile and profile need to be pulled.
What drives the range on a full addition: foundation type (pier-and-beam additions handle Schluter assemblies differently than slab-on-grade; in older San Antonio neighborhoods like Dignowity Hill, pier-and-beam is common and adds floor-membrane planning), the size of the wet areas, and whether we’re matching existing tile or starting clean. Every quote from Isaac Pruett and the Mason Remodeling Co San Antonio crew includes a written line-item price before work starts, with the Schluter components itemized separately. No change orders unless you change the scope. The completed work is covered by our 365-Day Done Right Promise: if it’s not right within a year of completion, we make it right at no cost to you.
DIY or Call Us?
Schluter Kerdi and Ditra installations are not dangerous in the way high-tension springs or live electrical work are, so a capable DIYer can technically buy the materials and attempt it. But the failure rate on homeowner-installed Schluter is high enough that Schluter only honors its warranty when the installer is a Schluter-trained professional. And here’s what DIY usually gets wrong: using the wrong thinset, skimping on Kerdi-Band overlap, setting tile before the membrane has fully cured, and forgetting that San Antonio tap water is hard enough to affect mortar bond when mixed too wet. If you’re going to try it, know what you’re checking, and stop when you’re unsure. If you’d rather know it’s done right, call us at (254) 269-5071 and we’ll bring the Schluter materials on the truck, installed to spec, with the written warranty behind the work.
FAQs
Schluter membranes and Kerdi-Board are rated for the life of the assembly when installed per Schluter’s written installation handbook, but in San Antonio’s climate, the real-world lifespan depends on substrate movement, temperature swings, and water exposure. A properly installed Schluter floor assembly in a San Antonio addition should outlast the tile above it, with most failures traceable to thinset choices rather than the membrane itself. Call (254) 269-5071 if you want us to inspect a suspect installation; we’ll tell you honestly whether it needs to be redone.
For seams, yes: if a Kerdi-Band or Kerdi seam has failed, we can sometimes expose it and re-bond the overlap without a full tear-out, provided the surrounding tile is stable and the membrane itself is intact. For membrane failures across a floor, a repair is usually not worth it, because water infiltration points are almost never isolated to one seam once movement has found a path. We’ll walk you through what’s repairable after looking at photos or a site visit.
A single shower-area Schluter waterproofing redo typically takes three to five working days including curing time. A full addition including Kerdi-Board wet walls, Ditra floors, and profiles typically runs six to fourteen weeks depending on scope and any existing framing work. We’ll give you a written schedule at the estimate so you know the timeline before you commit.
Yes. Our San Antonio crews carry Kerdi-Board in 1/2″ and 2″, Ditra and Ditra-XL, Kerdi membrane, Kerdi-Band in 5″ width, and the most common Schluter profile shapes (Rondec, Schiene, Quadec, Dilex) in aluminum and stainless. For unusual finishes or profile lengths, we order directly and have them in hand within a few days, so you’re never waiting for a part to arrive mid-job.
If you’re planning a Home Additions & ADU in San Antonio with Schluter systems specified, or you’re chasing a failure from a previous install, call (254) 269-5071. We’ll give you a straight price, we’ll tell you who’s coming before the visit, and we’ll put the whole scope in writing before a single panel is cut. As Isaac Pruett puts it: know who’s coming, know what it costs, know it’s covered – that’s the whole job before the job starts.
Written by Isaac Pruett, Owner, Mason Remodeling Co San Antonio at Mason Remodeling Co San Antonio, serving San Antonio and nearby areas.
