Waterproofing Singapore

Most leaks come from a few places: a failed membrane under toilet tiles, cracked grout or silicone around the shower, a loose floor trap, a leaking pipe joint, or cracks in a balcony or roof slab. The fix depends on which one it is.

• Crack or joint injection. PU resin is injected into a crack or joint to stop seepage. It suits a single leak point where the rest of the membrane is sound. No hacking.
• Regrouting and resealing. Worn grout and silicone are raked out and replaced. Cheap, and often enough when water only gets through at the shower corner.
• Coating over existing tiles. A clear or tile-top coating can slow seepage on a balcony or ledge. It is a stopgap, not a new membrane.
• Hack and redo. Tiles and screed come off, a new membrane goes down and up the walls, and the room is retiled. This is the only lasting fix when the membrane itself has failed.

If water is dripping into the flat below, read our guide on who pays for an HDB ceiling leak before you book anything. Damp ceilings often lead to spalling concrete and mould, so it pays to fix the source early.

Typical 2026 market ranges. The final quote depends on the cause, the area and whether tiles must come off.

Prices exclude repairs to the unit below and new fittings unless stated. For the hacking part alone, try our hacking cost calculator.

HDB sets out what must go in when wet-area finishes are replaced. From HDB's building works guidelines:

• A permit is needed to replace floor finishes, and to replace bathroom or toilet floor and wall finishes.
• New flats wait 3 years. Toilet floor and wall finishes can only be replaced after the first 3 years from the block's completion.
• Toilets and bathrooms need pre-packed waterproofing screed and a waterproofing membrane, turned up at least 150mm against the walls, kerbs and pipes.
• Kitchens and open balconies need pre-packed waterproofing screed, with the membrane and 150mm upturn required around the sanitary stacks for a 400mm radius.
• Floor traps get a UPVC grating with a long collar, and floor finishes plus screed must not exceed 50mm.

Overlaying new tiles over one existing layer needs no permit, but it does not add a new membrane. Renovation works are carried out by our partner V On Construction Pte. Ltd., listed in HDB's Directory of Renovation Contractors. Our HDB renovation permit guide explains how the permit is applied for.

• Ceiling stains under a toilet. Usually a membrane or floor trap problem in the flat above.
• Damp skirting outside the bathroom. Water travelling under the door kerb, often from a cracked kerb or missing upturn.
• Water under a cabinet. Often a sink pipe or tap joint, not waterproofing at all.
• Balcony seepage after heavy rain. Cracked screed, blocked drains or a failed coating at the edge.
• Choked floor trap overflowing. See our toilet and floor trap choke guide first.

Water service and sanitary pipe work is done by a PUB Licensed Plumber. Small jobs like resealing silicone can go through our handyman service.

1. Photos of the wet area from the door, plus close-ups of the floor trap, grout and any cracks.
2. Photos of the damage: the stained ceiling below, damp wall or bubbling paint.
3. When it leaks: all the time, only after showers, or only after rain.
4. Your flat type and block age, and whether the toilet has been redone before.
5. Whether the neighbour below has raised it, and any Town Council or HDB inspection notes.

WhatsApp them to +65 8561 0630. We tell you whether it looks like a spot repair or a full redo before anyone visits.

We take waterproofing jobs islandwide. Our workshop is at Mandai Estate, so Woodlands, Yishun, Sembawang and Admiralty are the quickest for us to reach, and we regularly cover Punggol, Sengkang, Ang Mo Kio, Tampines, Bedok, Jurong and the rest of Singapore.