Interior

Bathroom waterproofing: what happens under the tiles

A damp patch on a living-room ceiling very often comes from the bathroom above. Tiles and grout are not waterproofing: water that passes through the joints must be stopped by a membrane placed under the tiles.

The role of the under-tile system

A liquid membrane applied to the screed and turned up the walls creates a watertight tray. Tiles are then bonded over it. That invisible layer protects the structure, not the grout line.

The detail points

Wall-to-floor corners, shower drains, pipe penetrations, door thresholds, walk-in trays: each needs an embedded reinforcing band. More than nine out of ten leaks we repair come from these points, not from the flat field.

Upstands around the perimeter and across the whole shower zone
Reinforcing bands in every corner and around drains
Correct fall to the drain, with no reverse fall

Repairing an existing bathroom

Two routes: removing the tiles to rebuild the waterproofing properly, or a system approved over existing tiles where the substrate allows. We decide after inspection and moisture testing, not before.

The structural link

A long-running bathroom leak attacks the screed, the plaster and eventually the slab reinforcement. Treating it early costs a fraction of repairing a damaged ceiling.

Frequently asked questions

How do I know my bathroom is leaking?

A stain or blister on the ceiling below, grout that stays permanently dark, a damp skirting or wall base, a musty smell. A targeted water test confirms the source.

Does everything have to be broken out?

Not always. Depending on the tiles and substrate, an overlay system may be possible. The inspection makes that clear before the quote.

Need a diagnosis on your building?

Free inspection anywhere in Mauritius, written specification and warranted works. Call 606 2500.

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