Wet Area Waterproofing Works
FAQs
What counts as a wet area in HDB or condo?
A wet area is any indoor or outdoor space that’s regularly exposed to water from plumbing, rain, or use. In Singapore HDB flats and condos, wet areas include bathrooms, toilets, kitchens, open balconies, service yards, and shower stalls. Larger residential and commercial wet areas extend to swimming pools, planter boxes, jacuzzis, and rooftop wet decks. Each requires a different waterproofing system.
Why do wet areas need waterproofing?
Wet areas need waterproofing because tile grout and cement screed alone are not water-tight. Without a continuous membrane under the tiles, water seeps through the floor slab into the unit below, causing ceiling stains, rebar corrosion, and disputes with neighbours. In HDB flats, the upper-floor owner is generally liable for inter-floor leaks caused by failed waterproofing.
What happens if wet areas are not waterproofed?
If wet areas are not waterproofed, water penetrates the cement screed and slab within months, then drips into the unit below through hairline cracks and pipe penetrations. Damage includes ceiling stains, peeling paint, mould, electrical short circuits, and corroded rebar. In HDB flats, the affected neighbour can lodge a complaint, and rectification costs typically fall on the upper unit’s owner.
Does HDB require waterproofing during renovation?
Yes. HDB requires pre-packed waterproofing screed and a waterproofing membrane in any bathroom, toilet, kitchen, or open balcony before new floor finishes are laid. The membrane must be upturned at least 150mm against walls, pipes, and kerbs, and applied within a 400mm radius around sanitary stacks. A mandatory water retention test is conducted before tiles are laid.
How long does wet area waterproofing last?
Wet area waterproofing in Singapore typically lasts 5 to 10 years inside HDB flats and condos, depending on the membrane type and traffic. Cementitious membranes in bathrooms and toilets sit at the upper end. Open balconies and kitchens age faster due to UV and grease exposure. Recoating is usually needed once tile grout darkens or surface bubbling appears.
How do I know if my wet area waterproofing has failed?
Five clear signs that wet area waterproofing has failed: persistent damp patches on the ceiling of the unit below, dark stains around floor traps and door thresholds, loose or hollow-sounding tiles, mouldy grout that returns days after cleaning, and a musty smell. Failed waterproofing usually requires hacking, re-screeding, and a fresh membrane application by a registered contractor.