Most of the bathrooms we demolish in Charleston did not fail because of the tile. The tile was fine. What failed was the assembly behind it, and it failed for one of a handful of reasons we see over and over, in 1950s ranches in West Ashley and in ten-year-old houses in Summerville alike. If you are planning a remodel, or trying to figure out why your shower smells after every use, this is the list.
Mistake 1: treating tile and grout as the waterproofing
Tile and grout are a wear surface, not a barrier. Water goes through grout. Cement grout is porous by nature, and even sealed grout lets vapor through. In a dry climate a shower built with no membrane can limp along for years. In a place where the outdoor humidity is above 70 percent most of the summer, the wall behind the tile never dries out, and the framing eventually tells you about it. A proper shower has a continuous waterproofing membrane on every surface that gets wet, with the tile sitting on top of it.
Mistake 2: a pan with no slope, or slope in the wrong place
The shower pan has to slope toward the drain under the tile, not just on top of it. Builders in a hurry pour a flat base and let the mosaic tile carry the slope, or worse, slope toward a corner. Water collects under the tile, sits against the membrane, and finds any pinhole. The fix is a pre-slope, a properly clamped or bonded drain, and a flood test before tile ever goes down.
Mistake 3: unsealed corners and penetrations
Membranes are only as good as their seams. The inside corners, the curb, the valve opening and the shower head arm are where water gets in. Each one needs a preformed corner or a properly banded seam, and the penetrations need sealant designed for the membrane. We have opened walls where the membrane was perfect on the flat surfaces and open at every corner, which is the same as no membrane at all.
Mistake 4: drywall behind the tile
Older Charleston bathrooms, and some newer ones, have tile set directly on drywall or on greenboard. Once water gets to it, the paper face delaminates, the tile loses its bond, and the wall goes soft. Wet areas need cement board or a foam board backer, and that backer still needs a membrane over it. Greenboard is not waterproof; it is only slightly slower to fail.
Mistake 5: grout in the change-of-plane joints
Where a wall meets the floor, where two walls meet, and where tile meets the tub or the curb, the two surfaces move independently with temperature and humidity. Rigid grout in those joints cracks, and the crack is a direct path for water. Those joints should get a color-matched silicone that flexes. It is a small detail that separates a shower that stays dry from one that needs regrouting every two years.
How to tell your shower is already failing
A musty smell that comes back an hour after cleaning. Grout that darkens in the bottom course and stays dark. Tiles that sound hollow when tapped. A soft spot in the floor outside the shower. Paint bubbling on the other side of the shower wall. Any of these means water is behind the tile, and the fix is not caulk on top of it. It is demolition, a look at the framing, and a rebuilt assembly. Our demolition and substrate preparation page explains how we handle that first stage.
What a shower built for the Lowcountry looks like
Framing checked and repaired. Cement board or foam board on the walls. A pre-sloped pan and a bonded drain. A continuous waterproofing membrane on walls, pan, curb, niche and bench, with banded seams and sealed penetrations. A 24-hour flood test with the water line marked. Then, and only then, porcelain tile set with the right thinset, grouted with a high-performance grout, and finished with silicone at every change of plane. Every bathroom we build includes all of it, and we do not price waterproofing as an add-on, because a shower without it is not a finished shower.
Where we work
We rebuild showers across Charleston, Mount Pleasant, Summerville, North Charleston, West Ashley, Johns Island and Daniel Island. If you suspect your shower is leaking, request a free consultation and we will tell you plainly what we find.
WS Flooring is a licensed and insured bathroom remodeling and tile installation contractor based in Charleston, SC. Waterproofing is included in every shower we build, backed by a 1-year labor warranty.