The short answer
There's no single number for mould removal in Hong Kong, because a real quote comes down to three variables: how large the affected area is, how severe it is (light/moderate/severe), and whether the moisture source — a leak, condensation, or poor ventilation — needs fixing as well. Spraying the visible mould and actually tracking down why it's growing there are two different jobs, and they're priced differently. This isn't a market-rate survey — we're publishing our own bands as a reference point: Averta's preventive coating from HK$700, mould removal from HK$1,400, and removal plus prevention from HK$2,100, with a 6-12 month coating warranty and a free re-treat if mould recurs at the same spot within that period. Read on for why quotes vary between companies, where the DIY-vs-professional line sits, and what to ask before you hire anyone.
How mould removal is actually quoted
Three things drive the price, whichever company you ask:
- Affected area. A larger patch of mould means more material and more labour — the same logic as any home-service quote.
- Severity (light/moderate/severe). Surface spotting is a different job from mould that has penetrated the wall or caused paint to peel — the second usually needs more than a wipe-down.
- Whether the moisture source gets addressed. This is the variable that actually separates a lasting fix from a respray. Cleaning off visible mould is one job. Finding out whether it's poor bathroom ventilation, condensation pooling under an air-conditioner, or a leak coming down from the unit above — and dealing with that — is a different, more involved job. Skip the source check and mould usually comes back, which means paying again.
Averta's published bands (a reference point, not a market rate)
These are our own prices, published as a reference point — not a claim about what other companies or the market charge:
| Tier | From | Includes |
|---|---|---|
| Long-lasting preventive coating | HK$700 | Surface cleaning + preventive coating application |
| Mould removal | HK$1,400 | Thorough removal of all visible mould |
| Removal + prevention (full package) | HK$2,100 | Removal + preventive coating |
Full detail on what each tier includes and the warranty terms is on our mould removal service page. The coating warranty runs 6-12 months with a free re-treat at the same spot if mould recurs within that period — but if the underlying source hasn't been fixed (an ongoing leak from upstairs, for example), we flag that clearly at the assessment stage rather than folding it into the warranty as if it were covered.
Why quotes vary so much between companies
- Scope of work. Some quotes cover surface cleaning only (spray and wipe); others include a source check or even repainting/replastering. Wider scope costs more, but it also tends to last longer.
- Chemicals vs coatings. A one-off disinfecting spray and a long-lasting preventive coating have very different material costs and lifespans — coatings usually cost more upfront but hold up longer.
- Warranty length and terms. Whether there's a warranty, how long it runs, and whether recurrence gets a free re-treat all show up directly in the price. A cheap one-off service with no warranty looks cheap until mould comes back and you pay again.
- Whether there's an on-site assessment. A price quoted over the phone with no one having seen the affected area is usually a guess at "typical" conditions — it rarely matches the actual area or severity, and tends to get revised upward once someone shows up.
DIY or professional? Where the line sits
Not every mould problem needs a professional. Roughly:
- DIY usually works: a small patch on a non-porous surface (bathroom tile, glass, metal), a first-time occurrence, no sign of spreading. Wiping it down with a diluted bleach solution or a proper mould cleaner, plus better ventilation, is usually enough.
- Bring in a professional: mould recurring in the same spot, porous surfaces (plasterboard, wood, painted plaster), a large area, or anywhere that's previously flooded or had a leak. Surface cleaning tends not to hold in these cases — either the mould has taken hold inside the material, or the moisture source hasn't been resolved.
EPD itself doesn't recommend DIY pesticide or disinfectant use for mould cleanup, given the potential toxicity risk to whoever's doing it — and recurring mould is usually a sign the source hasn't been dealt with. Both are useful signals for deciding whether to call someone, not a hard rule.
What a proper quote should itemise
- Did they assess the area (in person or from photos) before quoting, or price it over the phone sight unseen?
- Does the quote include a moisture/leak source check, or surface cleaning only?
- What method or materials — chemical treatment or a coating? How long is the coating warranty?
- If mould recurs, is a re-treat at the same spot free, or does it get billed again?
- If the source turns out not to be resolved (a suspected leak, say), how do they handle that — do they still claim it's covered under warranty?
When mould points to a bigger building problem
If the source check turns up a structural leak — a ceiling or wall leak, for instance — no coating fixes that on its own; the mould will keep coming back until the leak stops. At that point it's no longer just a mould-removal question, it's a repair-responsibility question — who has to deal with it, landlord or tenant, is covered in Who Pays for Mould in a HK Rental?. If you'd rather get ahead of the wet season entirely, see our Hong Kong mould season preparation guide.