Bathroom fitting step by step: what happens and when

Strip out and repairs

Old suite, tiles and often plasterboard come out. This is when hidden problems appear: soft floorboards under the old toilet, rotten joist ends near the bath, or old leaks. Sound floors matter because tiles crack on a floor that flexes, so repairs happen here before anything new goes in.

First fix

Pipes are moved or renewed for the new layout, waste routes set, and cables run for lights, extractor fans and any heated towel rail or underfloor heating. Timber noggins are added in stud walls wherever a basin, wall hung toilet frame, towel rail or grab rail will be fixed. Bathroom electrics need to be installed by a qualified electrician.

Boarding and waterproofing

Walls in wet areas are boarded with moisture resistant or cement based board rather than standard plasterboard. Shower areas are then tanked, a waterproof membrane applied over the board and sealed at joints and corners. Most installers treat this step as essential in showers and wet rooms, because grout and tiles on their own are not waterproof.

Tiling and second fix

Tiling takes longer than people expect, especially with large format or patterned tiles that need careful setting out. After grouting, second fix follows: basin, toilet, shower valve and screen, bath panel, taps, mirrors and accessories, then silicone sealing. Doors often need trimming if the new floor is higher than the old one.

• Choose and order the suite and tiles before work starts.
• Decide on shower type, since it affects pipework and water pressure.
• Plan storage early, especially boxed in pipework that can become shelving.

Living without the bathroom

If it is your only bathroom, ask how the work is phased. Some fitters keep the toilet connected for as long as possible and return it quickly. Knowing the plan helps you arrange alternatives for the days without a shower.

Decisions to make before the fitter starts

The most common cause of delay on a bathroom is a choice left until the walls are open. Decide on the position of every fitting, the height of the basin and mirror, the type of shower valve, where towel rails and shelves go, and whether you want a niche in the shower wall. These all affect first fix, which happens early and is hard to change once boarded over.

Think about ventilation too. An extractor fan sized for the room and ducted to the outside does more to prevent mould and swollen doors than any paint. Ask how any boxing in around pipes will be finished and whether access panels are included, so a future leak can be reached without breaking tiles.

Questions we're asked about this