How to Tile a Bathroom

Start by removing old tiles and adhesive back to a sound surface. Tiling over old tiles is sometimes possible, but in a bathroom it hides the condition of the walls and any waterproofing behind them. Once the walls are bare, check for blown or crumbling plaster, loose plasterboard, damp, and walls that are badly out of flat. Problems found now are far easier to put right than after tiling.

Walls need to be sound, clean and flat. Weak or uneven walls are boarded with tile backer board, and plaster is primed before tiling. Floors need to be stiff and level: loose boards are fixed, timber floors are usually overboarded, and dips are levelled. If walls are being moved or pipes boxed in, that happens now, before any boarding or waterproofing.

Inside the shower and on the walls around the bath, tiles and grout aren't waterproof on their own. A tanking system, either a membrane or a liquid coating with tapes at joints and corners, goes on before tiling, following the manufacturer's instructions. This is the stage most worth getting right, because mistakes stay hidden until water damage appears.

Before fixing anything, plan where the tiles will fall. Mark a level line for the first full row, often just above the bath or shower tray rather than at the floor, and work out where the cuts land at corners, the window, the end of the bath and any niche. Aim for balanced cuts at both edges rather than a full tile on one side and a thin sliver on the other. On the floor, start from the doorway or the most visible line in the room.

Use an adhesive suited to the tile, the surface and the room, usually a flexible cement-based adhesive for porcelain, larger tiles, boards and floors. Mix only what you can use within its working time, spread it with a notched trowel suited to the tile size, and bed each tile firmly so there are no hollow spots. Follow the manufacturer's instructions for mixing and curing.

Straight cuts are made with a tile cutter; holes for pipes and shaped cuts need a tile saw or hole cutters. Ceramic is easier to cut than dense porcelain or stone. Clean, accurate cuts around taps, pipes and the window are what make a bathroom look professionally tiled.

Once the adhesive has cured, work grout fully into each joint and clean the surface before it hardens. In a bathroom, use a grout suitable for wet areas. Leave the joints between the tiles and the bath, tray or basin, and the internal corners, free of grout.

Those movement joints are sealed with a sanitary silicone, applied in a continuous bead and smoothed off. Natural stone may also need sealing before and after grouting.

Waterproofing, setting out on uneven walls, large-format tiles, natural stone and floors over timber are where small mistakes become costly to fix. Robert strips out, prepares, waterproofs and tiles bathrooms, and can redecorate the rest of the room once the tiling is done.