How a bathroom is tiled

The room is measured and the tile layout is planned so that cut tiles fall at the least visible edges and joints line up between floor and walls. Reference lines are marked on the floor and a laser or spirit level gives a true level line on the walls — usually at the top of the first row of wall tiles. The quantity of tiles, adhesive and grout is worked out from the layout, with a margin for cuts and breakage.

A floor trap is set into the slab where the shower water will collect, connected to the waste pipe. Its top is set to the finished floor height, so the screed and tiles can slope gently towards it.

Walls are plastered flat and plumb, and a cement–sand screed is laid on the floor with a gentle fall towards the floor trap so water never stands. Surfaces are cured and left clean, dry and free of dust before waterproofing.

Reinforcing tape goes into the floor–wall corners first. A waterproof coating or membrane is then applied over the whole floor, up the walls by about 300 mm, and higher behind the shower. It is dressed into the floor trap and left to cure before tiling.

Tile adhesive is mixed to the maker’s instructions and spread over a small area at a time, then combed with a notched trowel so each tile beds down evenly with full contact — no hollow spots that could crack.

Floor tiles are laid from the planned start line, pressed and tapped into the adhesive and checked for level and for the fall to the drain. Spacers keep every joint the same width. Anti-skid tiles are commonly chosen for wet floors. Tiles at the edges are cut to fit.

Wall tiles are fixed row by row from the level line, checked with a spirit level as each row goes up. Tiles for edges and around fittings are cut with a tile cutter. A decorative band can be set into a row. Joints on the wall are kept in line with those on the floor.

Once the adhesive has set, spacers are removed and the joints are filled with grout pressed in with a rubber float. The surface is wiped clean before the grout dries. Water-resistant or epoxy grouts are often used in wet areas.

Corners where the floor meets the walls, and internal wall corners, are sealed with a flexible sanitary silicone rather than grout, because these joints move slightly. Edge trims finish and protect exposed tile edges.

With the tiling complete and cured, the basin, shower and drain grating are fitted. The waterproofing, adhesive and grout under the tiles keep water where it belongs for years to come.