A shower that leaks rarely has a tile problem. It has a problem in the layers behind the tile.

In this Newton, MA bathroom we replaced a tub with a walk-in shower. Here is how it was built, from the inside out:

– Floor: a continuous pan liner with the edges turned up, then a mortar bed sloped toward a linear drain

– Walls: cement board instead of drywall, then a full waterproofing coat, including the corners and the niche

– Tile last: large grey marble-look wall tile and a hexagon mosaic floor, with the grout sealed after install

The spots that leak first: corners, the niche, the valve hole, and around the drain.

What’s under your shower tile? Tell us in the comments.

Flood testing a shower pan, and where leaks hide: Flood Testing a Shower Pan: What It Checks and Where Leaks Hide.

Sun Shore Construction is a licensed remodeling contractor serving Greater Boston.

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