Are tiles and grout waterproof?

No: tiles shed water but grout is porous and silicone perishes. The membrane underneath is the waterproofing; the tiles are decoration.

A continuous waterproof membrane system applied across the whole floor and up the walls, with taped corners and sealed penetrations, before tiling.

How do I know my wet room will not leak?

The quote names the tanking system by brand, corners and penetrations are sealed with proper tape and collars, and the floor fall is water-tested before tiling.

Can a leaking wet room be fixed?

Yes: localised failures can be repaired section by section; systemic failures need a wet-zone rebuild. The repairs page covers honest pricing for both.

Wet room tanking explained

Tiles and grout are not waterproof; the tanking membrane underneath them is the actual wet room. A proper job tanks the whole floor and walls, seals every corner and penetration with reinforcing tape, and water-tests the floor fall before tiling. Most wet room leaks trace back to one of those steps being skipped.

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The uncomfortable truth about tiles

Tiles shed water; they do not stop it. Grout is porous, silicone perishes, and movement opens hairline gaps no eye can see. In a conventional shower this barely matters because the tray catches everything. In a wet room the floor itself is the tray, so the waterproofing has to live underneath the tiles: a continuous membrane system across the whole floor and up the walls. That membrane is not an upgrade or a premium option. It is the room.

What a proper tanking system looks like

The membrane: a liquid-applied or sheet system, named by brand on the quote, rated for wet rooms. \"Waterproofed\" with no method named is a red flag.
Corners and joints: reinforcing tape bedded into every internal corner, every board joint, and the junction between floor former and wall.
Penetrations: pipe entries, the drain body and valve fixings sealed with purpose-made collars, not a hopeful smear of silicone.
The floor fall: a pre-sloped former deck on timber floors, a screeded fall on concrete, so water runs to the drain instead of pooling against the door threshold.
The water test: the formed, tanked floor flooded and checked before a single tile goes down. This is the moment a problem costs nothing; after tiling it costs everything.

How wet rooms actually fail

Nearly every failure story has the same anatomy. The membrane was skipped entirely (\"the tiles are waterproof, mate\"), or applied but the corners were not taped, or a screw through the floor former pierced it and nobody sealed the hole, or the fall was wrong and water sat against a threshold until it found a way through. The room then holds for a year or two, because water takes time to travel, which is exactly why the cowboy who built it is uncontactable by the time the ceiling below stains.

What to ask before you say yes

Three questions sort the professionals from the gamblers. Which tanking system are you using, by brand? How do you seal the corners and penetrations? And do you water-test the fall before tiling? Anyone who answers all three fluently has done this properly many times. Anyone who waves them away is pricing your leak. Every quote through this site names the system as standard, and our repairs page shows what we charge to fix the rooms where someone skipped it.