Most tile shower failures are not tile failures. The grout cracks, the tiles loosen, or mold appears behind the wall, and the tile gets blamed. In most cases, the real problem is what happened before the first tile was ever set: inadequate or absent waterproofing. This is the step we spend the most time on, and the one that is least visible when the project is done.
What Waterproofing Actually Does ¶
A tile shower is not inherently waterproof. Grout is porous. Even well-sealed grout allows some moisture through over time. The waterproofing layer, installed behind the tile on the walls and under the tile on the floor, is what keeps that moisture from reaching the framing and subfloor. Without it, water migrates into the wall cavity, promotes mold growth, and eventually causes structural damage. The tile may look fine for two or three years before the underlying damage becomes visible.
The Schluter Kerdi System ¶
Craftwork Renovations uses Schluter Kerdi membrane on all wet areas. Kerdi is a polyethylene fabric bonded to a fleece webbing on both sides. It is installed with unmodified thinset mortar, which bonds it directly to the substrate. The seams and corners are reinforced with Kerdi-Band. The result is a continuous, bonded waterproofing layer with no gaps. Schluter's system is tested and warrantied, and it is the standard we hold ourselves to on every shower project regardless of the overall project budget.
What We Look for Before Waterproofing Begins ¶
Before any membrane goes up, we inspect the existing substrate. Cement board or Schluter's own Kerdi-Board are acceptable substrates. Standard drywall, even moisture-resistant drywall, is not appropriate for wet areas and will be replaced. We also check that the shower pan slope is correct, typically a quarter-inch drop per foot toward the drain, and that the drain assembly is compatible with the membrane system. These checks add time to the project but prevent problems that would otherwise appear two or three years after completion.
Signs of a Shower That Was Not Properly Waterproofed ¶
If you are buying a home or assessing an existing shower, look for grout that is cracking or missing in the lower corners, tiles that sound hollow when tapped, any soft or spongy feeling in the floor near the shower, or visible staining on the ceiling of the room below. These are signs that water has been getting past the tile surface. In most cases, the repair involves removing the tile, replacing the substrate, and starting the waterproofing process from scratch. It is a more expensive fix than doing it right the first time.
If you are planning a bathroom remodel and want to understand exactly how we approach waterproofing on your specific project, we are happy to walk through it during the on-site estimate.