HDB Ceiling Leaking? Causes, Fixes & Cost (2026 Guide)

If you've noticed a brown water stain spreading across your HDB ceiling, or worse — water actively dripping — you're dealing with one of the most common (and most stressful) problems Singapore flat owners face. The good news: it's almost always fixable, usually without any hacking, and often in a single day.

Why Is My HDB Ceiling Leaking?

In nearly all cases, an HDB ceiling leak comes from one of three sources:

• The bathroom or kitchen of the unit above. Floor waterproofing in older flats degrades over 15–20 years, allowing water to seep down through the slab.
• The roof slab itself (only relevant if you're on the top floor, or there's a roof terrace above your unit).
• A leaking pipe embedded in the slab or running through the unit above — less common, but possible.

The location and pattern of the stain is usually a strong clue. A stain near the corner closest to a bathroom wall almost always points to bathroom floor seepage above. A stain that only appears after heavy rain points to the roof.

How Is It Fixed?

1. PU Injection (most common, no hacking)

For the majority of HDB ceiling leaks, the fix is polyurethane (PU) injection grouting. A specialist drills a series of small holes along the crack or seam causing the leak and injects an expanding resin that fills every gap and cures into a permanent waterproof seal. No ceiling demolition, no dust, and in many cases the active drip stops within hours.

2. Re-waterproofing the source (if PU injection isn't enough)

If the bathroom above has significantly failed waterproofing — not just a hairline crack — the more durable fix is to re-waterproof that bathroom floor using a no-hacking membrane system. This addresses the root cause rather than just sealing the symptom.

What Does It Cost?

For a standard HDB flat, PU injection ceiling repair typically starts from $350, depending on the number of injection points needed. If full bathroom re-waterproofing from above is required, costs are higher — see our full water leak repair cost guide for a complete breakdown.

What If My Upstairs Neighbour Won't Cooperate?

This is a common and understandably frustrating situation. A few practical points:

• In many cases, PU injection can be carried out entirely from your side of the ceiling — no access to the unit above is needed.
• If full bathroom re-waterproofing above is required and the neighbour is uncooperative, a written inspection report documenting the source can support a formal request or, if necessary, an HDB mediation case.
• We provide these inspection reports as standard with every site visit — useful documentation either way.

How Long Does It Last?

PU injection and waterproofing repairs from Best Waterproofing SG come with a 2-year written warranty. In practice, properly executed PU injection repairs commonly last well beyond that, provided the source crack doesn't reopen due to structural movement (rare).

Bottom Line

A leaking HDB ceiling is rarely a reason to panic — but it is a reason to act quickly, since water damage compounds the longer it's left untreated. A free inspection will tell you exactly which of the above fixes you need and what it will cost, with no obligation.