Bathroom Renovation Done Properly: Why Waterproofing and Sequencing Decide Whether It Leaks

A bathroom renovation looks like a tiling and fittings job. The real work is underneath, in waterproofing, drainage and the order in which each step happens. Get these wrong and the new finish simply hides a leak waiting to happen.

Why bathroom leaks are so costly

A leak does not stay in the bathroom. It travels into walls, ceilings and, in apartments, into the unit below. That turns a repair into a dispute, with damage to someone else's property and an insurance claim on top.

Start with the services

Old pipework behind walls should be assessed before anything is tiled over. Replacing corroded or leaking pipes while the walls are open costs far less than doing it after finishing. Supply pipes should be pressure tested before they are covered.

Falls and drainage

The floor must slope toward the drain with no low spots where water can sit. This is set in the screed before waterproofing, so it is a civil step as much as a plumbing one.

Waterproofing is the key step

The floor and the lower part of the walls, and the full height in shower areas, need a continuous waterproof layer, with careful detailing at corners, drains and pipe penetrations. After it cures, water should be held on the floor for a set period, typically a day or more, to prove it does not leak before tiling starts.

Tiling and finishing

Tiles go on only after the waterproofing has passed its test. Movement joints and flexible sealants at corners and junctions allow for normal building movement without cracking.

Electrical safety and ventilation

Bathroom fittings need appropriate water-protection ratings and proper earthing and bonding. Ventilation matters too: a bathroom without extraction will grow mould, however good the tiling.

What to do last

Shower glass, sanitary fittings, mirrors and accessories go in last, once surfaces are finished, so nothing is damaged during the main works.

Renovating a bathroom? Book a free survey and we will check the existing pipework and waterproofing before any tile is chosen. See our waterproofing and tiling services.