BATHROOM WATERPROOFING
Bathroom Waterproofing: HK$3,500 or HK$80,000? First, Find Out Which One You Need
Quick answer
Bathroom waterproofing pricing spans a wide range — anywhere from HK$3,500 to over HK$80,000 — because it depends entirely on which job you actually need: (1) surface re-waterproofing (applying a waterproof coating over the existing plaster/tile without demolition), reference range HK$3,500-7,000; or (2) full strip-and-rebuild (demolition to slab, new screed, new waterproofing membrane, re-tiling), reference range HK$30,000-80,000+ depending on scope. A lot of quotes in this market give a single headline number without telling you which job it covers — we think that's the wrong way to price this, and we always confirm which situation you're in before quoting.
Why the price range is so wide
Bathroom seepage has two fundamentally different root causes: ageing plaster/coating with a sound structure and intact waterproofing membrane (surface re-waterproofing is enough), versus a failed waterproofing membrane letting water through to the flat below (needs a full rebuild). Using the wrong fix — surface-only work when the structural layer is already compromised — just fails again quickly, so you end up paying twice; the reverse (a full rebuild when the structure is fine) wastes money you didn't need to spend.
- Bathroom size — directly drives material and labour cost.
- Tile/fixture grade — the spec of replacement tiles, taps, showers, etc.
- Demolition extent — floor only, or floor and walls.
- Drainage/pipe scope — relocating floor drains or replacing pipework adds significant work.
- Access and waste-removal constraints — building-specific limits on loading/unloading and debris disposal push costs up.
- Building age and slab condition — older buildings are more likely to have structural-layer seepage, sometimes needing reinforcement.
Pricing
| Approach | Reference price | When it applies |
|---|---|---|
| Surface re-waterproofing (no demolition) | HK$3,500-7,000 | Ageing plaster/coating with a sound structure and intact membrane — most bathroom cases |
| Full strip-and-rebuild | HK$30,000-80,000+ | Failed waterproofing membrane, seepage into the flat below, or structural-layer damage |
Both ranges are compiled from published market pricing, not our own invoiced data. Any real quote should start with an on-site inspection (a leak-detection service can confirm the source) before pricing against the drivers above.
Licensing scope
Per the Buildings Department's FAQ (loaded and verified 2026-07-13), home renovation and simple works inside a flat — plastering, laying tile finishes, repairing or replacing sanitary fitments — are exempted building works under the Buildings Ordinance: no prior BD approval and no registered contractor required. That means internal bathroom renovation (including its waterproofing step) generally sits inside that exemption. Where a job opens up tile or screed layers, it falls under Minor Works items 1.62/2.34 and must be done by a registered minor-works contractor; works touching building drainage or structure are also outside the exemption.
Warranty
Full-rebuild-tier warranties are typically the longest in the market (up to around 10 years), while surface-tier warranties are shorter (roughly 1-3 years by market convention). Warranty terms should state trigger conditions in writing — always confirm before booking.
Not sure which situation you're in? Send a photo on WhatsApp for an initial read
Our WhatsApp and phone hotline are launching soon — please use the form below in the meantime and we'll reply as quickly as we can.
Frequently asked questions
How do I know which situation my bathroom is in?
The most reliable way is a leak-detection assessment first, to check the condition of the waterproofing membrane and locate the source. We don't recommend booking a full rebuild based on a visual guess or a verbal opinion alone.
Is it normal for a quote to give just one number without saying which approach it covers?
No — that's one of the market's common opacity tactics. A responsible quote should state whether it's surface-level or full rebuild, what scope is included, and what materials are specified, not just a single headline figure.
Do I need a licensed contractor for bathroom waterproofing?
If the job involves removing tile or screed layers, yes — it must be done by a Buildings Department-registered minor-works contractor. Internal bathroom renovation itself (plastering, tiling, sanitary-fitment repair or replacement, including the waterproofing step) is exempted building works per the Buildings Department's FAQ — no approval or registered contractor needed — except any part touching building drainage or structure.