How you know the membrane has failed
- A damp patch on the other side of the shower wall, at or just above skirting height
- A stain on the ceiling of the room below an upstairs shower
- Loose, drummy or lifting tiles in the shower floor
- Persistent musty smell in the bathroom with no visible mould
- Grout that stays dark and never dries out between uses
- Skirting, door frames or laminate lifting on the far side of the wall
Every one of these means water is already in the structure. Re-grouting seals the visible joint and leaves the water exactly where it is.
What a correct installation involves
- Strip the tiles and the existing bed back to a sound substrate.
- Check and correct the falls to the waste — a shower floor must actually run to the drain, and a surprising number do not.
- Prime the substrate.
- Install the bonded membrane across the floor and up the walls: a minimum of 1.8m in the shower area, 150mm elsewhere in the wet zone.
- Tape and seal every internal corner, wall-floor junction and pipe penetration with purpose-made banding — corners are where these systems fail.
- Dress the membrane into the waste with a puddle flange so there is a sealed connection, not an overlap.
- Flood test for 24 hours before a single tile goes back on.
- Tile with a suitable adhesive and a flexible sealant at the movement joints.
The 24-hour flood test is the step that gets skipped. Insist on it. It is the only opportunity to find a fault before it is buried under tiles.
Common questions
How much does it cost to re-waterproof a shower?
About R7,000–R16,000 for a standard shower, stripped and rebuilt. Tile choice moves it most — the waterproofing itself is a modest part of the total; the demolition, tiling and making good are the bulk.
Can you waterproof a shower without removing the tiles?
There are surface-applied sealer products sold for this and they buy time at best. If the membrane under the bed has failed, the water is already in the screed and the wall. Doing it properly means the tiles come off.
Is waterproofing paint enough under shower tiles?
No. A single-coat brush-applied waterproofer with no corner banding and no puddle flange is not a system, and it is what we find under most failed showers. The corners and the waste connection are what matter.
How long does a shower waterproofing job take?
Typically five to eight working days: strip, prepare, membrane, 24-hour flood test, tile, grout and seal, plus curing time between stages.