COST EXPLAINER
How Much Does Waterproofing Cost in Hong Kong — and Why Do Quotes Vary So Much?
Quick answer
Waterproofing costs in Hong Kong vary widely, and the main reason isn't simply 'which company is cheaper' — it's that the unit, scope and approach behind each quote differ. The ranges we currently have reliable market evidence for: injection grouting HK$2,500-3,500 per spot; leak detection with report HK$8,000-12,000; bathroom surface re-waterproofing HK$3,500-7,000, full rebuild HK$30,000-80,000+; roof surface coating from HK$130/sq ft, full removal from HK$260/sq ft. Window seepage and surveyor reports don't yet have reliable published data — this article and our pricing page deliberately carry no figure for either.
The ranges we currently have evidence for
| Service | Reference price |
|---|---|
| Injection grouting (PU) | HK$2,500-3,500 / spot |
| Leak detection with written report | HK$8,000-12,000 |
| Bathroom waterproofing (surface, no demolition) | HK$3,500-7,000 |
| Bathroom waterproofing (full strip-and-rebuild) | HK$30,000-80,000+ |
| Roof waterproofing (surface coating) | from HK$130/sq ft |
| Roof waterproofing (full removal) | from HK$260/sq ft |
| External wall waterproofing / crack repair | from HK$15,000 (scaffolding extra) |
These figures are compiled from published market pricing (checked 13 July 2026), not our own invoiced data. See our pricing page for the full table with units and notes.
Why quotes for the same service can vary so much
There are two main reasons. First, unit ambiguity — 'per spot' and 'per job' pricing for injection work are entirely different bases, and that ambiguity is exactly the market's documented fraud pattern (one case escalated from a HK$2,500 quote to HK$26,000). Second, scope differences are real — 'bathroom waterproofing' can mean surface re-waterproofing (HK$3,500-7,000) or a full rebuild (HK$30,000-80,000+), a roughly 23x spread, depending on whether the waterproofing membrane has failed or water has already reached the flat below.
- Area size and demolition scope — drives material and labour cost.
- Drainage/pipework scope — relocating or replacing pipes adds significant work.
- Access constraints (scaffolding, loading/unloading, building height) — especially for roof/external-wall jobs.
- Building age and structural condition — whether the structural layer is damaged determines surface-only vs full rebuild.
How transparent pricing protects you
A trustworthy quote always states its pricing unit (per spot / per sq ft / per job) and scope, and writes down a spot-count cap before work starts. Our pricing page publishes every range we currently have evidence for — and is equally upfront about what we don't — because that transparency is itself the first line of defence against a mid-job upsell.
Items with no published price yet
Window seepage and surveyor reports don't yet have enough reliable market pricing evidence to support a responsible published range — we'd rather tell you we don't have the data than give you a number that could mislead. Pricing for both is quoted only after an on-site assessment.
Related reading
- Our Price List: We Only Publish What We Have Evidence For
- PU Injection Grouting: HK$2,500-3,500 per Spot, Capped Before We Start
- Leak Detection with a Written Report: You Can't Fix What You Can't Find
- Bathroom Waterproofing: HK$3,500 or HK$80,000? First, Find Out Which One You Need
- Roof Waterproofing: Even the Government Says This Is on You
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Frequently asked questions
Is HK$2,500-3,500 the price for the whole injection job?
No — it's the price per spot. That unit matters a lot, and you should always confirm it in writing before booking.
Why can bathroom waterproofing range from HK$3,500 to over HK$80,000?
Because there are two completely different approaches — surface re-waterproofing and full strip-and-rebuild — and which one you need depends on the condition of the membrane and structure (see the bathroom waterproofing service page). A single headline number isn't a responsible way to quote this.
Why don't window seepage and surveyor reports have a published price?
Because we don't yet have enough reliable market data to support a responsible published range for either — causes and case complexity vary too widely. Actual pricing is quoted after an on-site assessment.