Waterproofing Behind Bathroom Tile in Riverside

By the time the last row of tile goes up on a shower wall, the waterproofing is already hidden, and the whole job depended on what was done before it, as the notes at riverside kitchen and bath remodeling touch diva describe. In Riverside, CA the dry climate makes that hidden layer easy to neglect, since a slow leak behind the wall of a kitchen and bath rarely shows a stain before the framing is damaged.

Tile and grout are not waterproof

Grout is porous and the joints between tile let water through in small amounts every time someone showers. The water is supposed to be caught by a layer behind the tile and sent down to the drain. That layer is the waterproofing, and when it is missing or has a hole in it, the water goes into the wall instead.

Cement board and foam board

Cement board is a heavy backer board, cut and screwed to the studs, that does not rot when it is wet, though it is not waterproof by itself and it soaks water up. Foam board is lighter, cuts with a knife and often arrives with its own banding and sealing parts. Either works when the manufacturer's seam and fastener steps are followed. Plain drywall behind a shower is the failure that shows up whenever old bathrooms are opened.

Membranes, liquid and sheet

A liquid membrane is rolled or brushed on in coats, with a fabric patch at corners and seams, and it has to reach the film thickness the label calls for. A sheet membrane is bonded to the wall with thinset and the seams are overlapped and sealed. The craft is in the details: the corners, the valve and showerhead penetrations, the curb, the bench and the niche. Each of those gets its own patch or sealing kit.

Slope and the shower pan

A shower floor needs a steady fall toward the drain, with a waterproof layer below the tile and the mortar. A shower pan that is flat or tipped the wrong way holds water against the grout for hours, and it dries slowly. The membrane on the floor has to run up the wall and over the curb, so the pan is one continuous bowl with no seam low down where the water collects.

Why Riverside hides leaks

Hot dry summers and little rain mean the framing behind a leaking shower can dry out between uses, so the damage creeps along for years before a soft floor or a musty smell appears. Mild winters with occasional freezes rarely bring condensation trouble, but a crack in the membrane keeps wetting the same stud month after month. Old porcelain tile on a mortar bed, common in houses from the early and middle twentieth century, can look perfect while the bed below has gone soft.