How to build a waterproof tile shower

Tiler replacing wall tile in shower cubicle image by Bryan Clark from

Tiling a shower requires that you take additional measures to ensure that the surface of the tile remain waterproof regardless of how much water hits the tiles. Water that seeps beneath the tile can damage the surface beneath, breaking down the surface, and leading to the growth of mould and mildew. While building a waterproof shower using tile alone isn't possible, a combination of materials can build up the water resistance. With all materials in place, the tile provides the final proof against the damaging effects of the constantly wet shower environment.

Prepare the walls for tile installation. Remove any obstructing items like shelves, wall trim and fixtures. Remove any wallpaper if present and dull the surface of painted walls with sandpaper, removing any finish.

Install the tub or shower base according to the manufacturer's instructions before the tile installation. Cover the drainage hole with a dropcloth before tiling the rest of the enclosure.

Place a vapour barrier of plastic sheeting against the wall where you intend to install the tiles. The barriers should rise to a height at least six inches above the showerhead to protect the wall from splashing. Spread a layer of asphalt mastic onto the wall to hold the plastic in place, raising ridges in the mastic using the notched edge of a notched trowel. Wait 30 minutes for the mastic to begin to set and then place the plastic along the wall's surface. Overlap the edges of the plastic by four inches, and then secure the overlap flaps with strips of fibreglass tape. Place a second layer of the mastic over the sheeting.

Place a layer of cement board onto the mastic covering the plastic sheeting as a subsurface for your tile. The cement board should begin ΒΌ-inch above the base of your tub or shower base and rise to the top of the tiled area. Cut holes in the board using a utility knife prior to placement for fixture fit. Locate the wall studs in the shower area and secure the boards in place by nailing them to the studs using roofing nails. Seal the seams in the boards by covering them with fibreglass tape. Place a bead of caulking along the edges of the board against the walls.

Mix a batch of thinset mortar according to the manufacturer's instructions to the consistency of peanut butter. Spread a layer of the mortar over the fibreglass tape to help complete the seal.

Create a guideline for the tile placement by creating a horizontal line 1/8-inch above the floor of the tile wall.

Mix more of the thinset mortar and place a layer of the mortar onto the wall using a notched trowel, raising ridges in the thinset with the notched edge. Only cover a four-foot square portion of the wall at a time in order to avoid having the thinset dry during tile placement. Place the tile onto the wall using the mortar as an adhesive, and using the guideline to create a level row. Place tile spacers between the tiles to create uniform joints. Tiles used should be waterproof, such as glazed ceramic. Cover the surface of the wall rising to the edge of the cement board. Place the tiles so that you use as many full tiles during the installation as possible, with the edges of the wall being covered using edging tiles. Cut tiles when necessary using a tile cutter rented from a home improvement store or equipment rental shop. Wait overnight for the mortar to dry.

Remove all tile spacers and fill the joints between the tiles with waterproof grout. Apply the grout to the tile surface with a grout float, and then push the grout into the joints, filling them. Remove excess grout from the surface of the tiles with a damp sponge within 15 minutes to prevent the grout from drying in place. Wait 30 minutes after applying the grout to wipe away any residue from the surface of the tiles using a lint-free cloth.

Place a bead of caulking at the edges of the tile surface against the wall, and along the foot of the tiled surface against the tub or shower floor to create a waterproof barrier protecting the subsurface.

Wait two weeks to allow the grout to set enough for sealing. Seal the grout by brushing a layer of tile and grout sealant onto the grout using a squeegee. The sealant applies an additional layer of waterproofing to the porous grout. Allow the sealant to dry for 48-72 hours before installing the fixtures and using the shower.

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