San Leandro Pan, Kerdi Waterproofing, Bench, Notch Surround, April, 2026

This San Leandro shower got the full build: a custom pan, Kerdi waterproofing, a built-in bench, a niche, and a tiled surround. The existing post says I’m not a fan of the Kerdi system, and that’s still true, but I know it well, and it was the right fit for this job.

Kerdi is a surface waterproofing system. With a traditional pan, the waterproof liner sits buried under the mortar bed. Kerdi goes on the surface instead, directly behind the tile. For the pan, that meant a Kerdi drain and a sloped mortar bed, with the Kerdi membrane set over the top of the mud bed. The membrane then continued up the walls and over the bench, so the whole shower is wrapped in one continuous waterproof layer, with overlapping seams and preformed pieces at the corners.

The bench, the top edge of the surround, and the edges of the niche are all finished in Schluter edging. On a job like this, the metal trim gives every exposed edge a clean, durable finish that protects the tile edge from chipping and holds up to daily use. It’s a different call from the San Leandro surround we did years ago, where we skipped edging because the old walls were too far out of square and plumb. Here, the surfaces were true enough for the trim to sit clean and straight.

The floor is a penny mosaic. Small round tiles look great underfoot and give good grip in a wet area, since the grout lines add traction. They’re also among the fussiest tiles to set. Small tiles want to shift while the mortar cures, and a penny round pattern shows every drift. The sheets have to be set carefully and checked often, and the cuts at the drain and walls are done piece by piece with tile nippers.

The result is a fully waterproofed shower with a comfortable bench, a clean niche, and a floor that’s as practical as it is good-looking.