Wall seepage, rising damp, or a cold wall

Last updated 31 October 2026.

Three wet walls get the same brown paint and they are not the same fault. The first wets in a storm and dries, slowly, over the next day. That is rain finding a crack, a joint, or a failed drip on the outside face. On an HDB block that face is common property. The Ministry of National Development has said external walls are maintained by the town council, and that residents who meet seepage from outside should report it there. HDB refers cases it receives to the council. In Parliament on 8 April 2025 the Senior Minister of State said HDB assisted town councils and flat owners with 859 complex water-seepage cases in 2024, including external walls and leaks from the flat above. That number is HDB’s count of complex cases it touched, not a count of every stain in Singapore, and not a prediction for your block.

The second wall has a tide mark, often under a metre, with powdery salts and a skirting that has swollen, on a ground floor that touches soil. That pattern is rising damp: moisture wicked from the ground because a damp-proof course is missing, bridged by a flower bed piled against the wall, or by render that runs down past the course into the soil. It is a landed-house and old-shop diagnosis. It is a poor fit for a 12th-storey HDB bedroom, where there is no soil and the water is either rain through the facade or a wet room on the other side of the wall. Treating a high-floor HDB wall with a rising-damp slurry is how a facade leak gets an interior cosmetic.

The third wall grows mould in the shape of the wardrobe that stands against it, or on the wall the aircon blows across, and it is dry to the touch by afternoon if you move the furniture. That is condensation. Humid air hits a cool surface and leaves water. A membrane injection does nothing for it. Move the wardrobe 50mm, run the exhaust when you shower, and wash the mould once the surface stays dry. The mould pages on this site are the wash. They are not a licence to hack the wall.

A bathroom wall that wets the bedroom only when the shower runs is none of the three. It is a membrane or a pipe in the wet room. Pond the floor and run the shower as separate tests. If only the shower does it, the membrane upturn on that wall has failed or a pipe in the wall is open. The waterproofing page and the pipe page split those. Do not inject the bedroom face and leave the shower untouched.

Negative-side treatments, the slurries sold for the inside of a leaking concrete wall, hold back water that is already in the concrete. They can be a last coat after the outside crack is closed. Used first, they trap water in the wall. The paint then blows, the salts return, and the outside crack is still taking rain. On an HDB facade you may not be allowed to touch the outside at all. Pay the council’s process. A private injector who offers to “finish it from inside this week” on a wall the council has not released is selling you the wrong side.

Comparative moisture readings are a map, not a verdict. Pinless meters read a cold, salty or freshly painted wall as wetter than a dry internal partition. Take a reading on the stain and a reading on a wall in the same room that has no business being wet. Write both down. We will not publish a percentage that “proves” seepage. Spalling, where the concrete is popping and the steel is rusting, is the spalling page, S$150 to S$300 for a small patch when that sentence matches. A hairline repaint after the wall is actually dry is S$150 to S$400. Paint on a live seepage is a second invoice.

Homey Furnishing Pte. Ltd. (ACRA UEN 202018148K), 27 Mandai Estate, #06-10 Innovation Place, Singapore 729931, invoices permit-exempt leak checks, regrouting, silicone, and making-good after the water has stopped. V On Construction Pte. Ltd. (ACRA UEN 201611708H), on the HDB Directory of Renovation Contractors, invoices an HDB renovation permit when bathroom finishes are hacked or a new membrane is laid under new tiles. A concealed or new water-supply pipe is a PUB licensed plumber. Homey Furnishing is not that plumber and does not publish a waterproofing warranty term.

Curtains, blinds and roller shades are not part of this booking. Fabric window treatments are a different product, and these pages do not quote them.

A week of notes beats a same-day injection. Write rain, showers and aircon as separate columns.

1. Photograph the patch in the rain and on a dry afternoon. If it only exists behind furniture, pull the furniture out before you call anyone.
2. If the flat is HDB and the wet wall is an external wall, report it to the town council on the S&CC bill. Keep the photos.
3. If you are on the ground and the mark is a horizontal tide with salts, say so. That is the rising-damp conversation, and it is quote on inspection.
4. If the other side of the wall is a shower, run the shower test before you treat the bedroom.
5. Do not hack a household shelter wall that happens to be the wet one.

The same brown patch is a council job, an MCST job, or your own ground floor, depending on the wall it sits on.

On a landed ground floor the sequence is to remove the bridge first. Soil, a concrete path or render that covers the damp course has to come off the face. Then the plaster that is full of salts comes off to a line above the tide mark, the wall is left to dry, and a new plaster that tolerates salt goes back. Injected creams are a method for a brick wall that has no course, not a paint for an HDB facade. A chemical damp course in a reinforced-concrete HDB wall is the wrong tool. We will not sell one. The work on a real landed wall is quote on inspection because no band for it exists on this site.

Good work leaves a gap between the new plaster and the soil, and does not seal the wall with a plastic paint the week it was opened. Sloppy work paints over salts, which return as blisters, or injects a cream into concrete and invoices it as a guarantee. We publish no such guarantee.

Pick the row from the calendar, not from the product the contractor arrived with.

A seepage quote should name the side of the wall they will work on, and who owns that side.

1. Is this the external face, and has the town council or MCST released it?
2. What in the last two weeks of weather matches the stain?
3. Are you injecting from inside because you cannot reach the outside?
4. If you say rising damp, where is the tide mark, and what is bridging the damp course?
5. What moisture readings will you write down, and against which dry wall?
6. Which HomeySG price are you using? If none, the answer is quote on inspection.

Report external-wall seepage to the town council, or to HDB if you cannot find the council, knowing HDB says it will refer those cases. Do not pay a private bill to stay out of a queue and then discover the council was going to do the facade. Condo owners write to the MCST and keep a copy. The strata page is for leaks from the lot above, which is a different argument.

Falling concrete is not a paint job. If pieces are coming off a common facade, the council again, and keep people out of the drop zone. Water into a socket: isolate. Shelter walls stay closed even if they are the wet wall.

How you're charged

A leak or waterproofing job that already has a sentence on HomeySG uses that sentence. Nothing in this table is a fuel surcharge, and the handyman hour is not added on top of a band unless the written scope says so. A membrane, a balcony, a planter, a roof, an epoxy-grout system, or a listening survey with no matching row is quote on inspection.

Who is allowed to do the work

HDB’s renovation pages split a coat of silicone from a hacked bathroom. Replacing toilet wall and floor finishes is not allowed for 3 years from the completion date of the block, because a membrane sits on the screed. After that, a replacement uses pre-packed waterproofing screed, a membrane upturned at least 150mm at walls, kerbs and pipes, a UPVC floor-trap grating with a long collar, and a water test. Fines for unauthorised work are already written on the permit guide as up to S$5,000. Homey Furnishing does not sign the permit invoice.

• Regrout, a silicone zone, hollow-tile injection and a stain repaint after the water has stopped stay on the published rows. They do not replace a membrane.
• Opening the bathroom floor or wall finishes is V On Construction when the flat is HDB and the work needs a permit.
• PUB’s leak leaflet says it is an offence under the Public Utilities Act to engage an unlicensed worker for plumbing work. A concealed or new supply pipe is a licensed plumber. An exposed trap is a different visit.
• External walls of an HDB block are common property. The town council on the S&CC bill is the first report, not a private injector.
• SCDF does not allow hacking of household-shelter walls, floor slabs or ceiling slabs to chase a pipe. The leak is found another way.
• A window-frame leak is the window sealant page. Exterior rivets and stays stay with a BCA approved window contractor.
• Curtains, blinds and roller shades are not quoted here.

Ways to keep the bill smaller

• Photograph the stain, the wet room, and the water meter before anyone hacks. A hack that destroys the evidence is a second problem.
• Run one test at a time. Shower, flush, aircon and rain on the same afternoon make a useless log.
• If the joint is only mouldy silicone, the published zone is S$80 to S$150. That is not a membrane.
• If the ceiling is already dry and the source is fixed, the hairline repaint is S$150 to S$400. Paint on a live leak is how the stain returns.
• Move the wardrobe and wait a dry afternoon before you book an injection. A condensation patch does not need a membrane.

WhatsApp the photos to +65 8561 0630.

Seepage injection and rising-damp work have no published band. The small make-good rows apply only after the wall is dry and only when the sentence matches.

Anything not in that table is quote on inspection.

WhatsApp the photos to +65 8561 0630. The reply uses a band already printed on HomeySG, or it says quote on inspection.

Official pages, not a legal opinion

The 859 cases and the town-council duty are from the parliamentary record. They are not a service standard we are offering, and they are not legal advice about your flat.

• Parliament, 8 April 2025. External HDB walls are town-council common property. HDB assisted on 859 complex seepage cases in 2024.
• HDB ceiling leaks. Common-property leaks go to the town council. Interior maintenance stays with the owner.
• HDB toilet finishes. A wet bedroom wall beside a bathroom is not a reason to hack toilet tiles inside the 3-year ban.
• SCDF shelter. Shelter walls are not the place to chase a stain.

• Mould once the wall is dry
• Mould removal
• Spalling concrete
• If the shower is the source
• If the water is from above
• Handyman price list