Ceiling leak repair in Singapore.

It depends on which repair the assessment calls for. Where the toilet above must be re-waterproofed, renovation platforms' guides put the basic works of one bathroom, hack, waterproof and tile, at about S$3,000 to S$9,000 before fittings. PU injection for a crack in the slab is S$300 to S$1,200 per job in one waterproofing contractor's 2026 price guide. Making good a spalled ceiling below, after the leak has stopped, was put at S$300 to S$1,200 by a home magazine in November 2024. A roof is priced per square metre; see the roof waterproofing page. Any figure quoted before a flood test of the room above is a guess.

The floor slab between two flats is a shared structure. HDB's letters describe its Goodwill Repair Assistance scheme: HDB pays 50 per cent of the repair cost, the remaining 50 per cent is shared equally between the upper- and lower-floor owners, and once both agree HDB arranges the contractor, whose work can include a new waterproofing membrane on the floor of the upper unit and skim coating, sealer and paint on the ceiling below. The scheme covers slab leaks from wear and tear; leaks from water supply pipes within a flat sit outside it.

BCA's Strata Management Guide 13 on water seepage, first published November 2023: where a ceiling shows dampness or water penetration, the defect is presumed to be in the unit immediately above unless evidence shows otherwise, and both owners should jointly investigate the cause. Where the seepage originates from common property, such as the roof or an external wall, it is the management corporation's duty to keep it in good and serviceable repair. Disputes that cannot be settled can go to the Strata Titles Board.

Position and timing provide clues, not a diagnosis. A stain after upstairs water use may point to a wet area or plumbing. A top-floor stain that grows after rain may point to the roof or external seepage. Record when it appears and arrange an inspection. A professional should choose suitable tests under safe, agreed conditions; do not block a drain and flood the area yourself.

Not by coating the ceiling: a waterproof coating, a sealer or a fresh coat of paint on the ceiling below only hides the problem. The one repair made from below is PU injection for a crack in the slab, which drives resin into the crack from below or above and seals it, at about S$300 to S$1,200 per job in one contractor's 2026 price guide. A failed membrane cannot be repaired from below: it lies under the tiles upstairs and has to be hacked out and re-laid.

The toilet above: hacking one to three weekdays, because HDB allows noisy work only on weekdays from 9 am to 5 pm; the membrane one day; the flood test the following day, held for a day; then tiles and grout. Injection is usually a day plus curing time. A roof depends on area and weather. The ceiling below is made good only after the source is fixed and the slab has dried.

That is spalling concrete from a long leak: the reinforcement has rusted and pushed the concrete off. Stop the leak first, then a contractor hacks off the loose concrete, treats the steel and patches it. A home magazine in November 2024 put making good at S$300 to S$1,200, from a phone-sized patch to a whole toilet ceiling. HDB lists spalling concrete among the defects its new-flat warranty covers; check the current terms.

Notify them in writing with photographs, then ask HDB to inspect. HDB's Goodwill Repair Assistance scheme exists to break exactly that impasse: once both owners agree, HDB arranges the contractor. In a condominium the management corporation investigates first; where the dispute cannot be settled, BCA's guide points to the Strata Titles Board.

An applicator in the Rayson network. Rayson makes SealForce WB20 for the toilet above and SealForce RC40 for the roof, and publishes their technical data; the applicator finds the source, flood-tests, quotes, invoices, repairs and warrants its workmanship. The applicator's first choice is a Rayson product. Where the job is not one a Rayson product covers, PU injection for example, the applicator uses another suitable material. Rayson's material warranty applies to Rayson membranes.

Dated photographs of the stain, ideally one after the household upstairs has used water and one after rain; photographs of the room directly above (toilet floor, trap, shower wall and threshold, or the roof); the unit type (HDB, condo or landed) and floor; and whether the neighbour above is cooperating. We respond within one working day and introduce an applicator for the site visit.