Short answer
A cleaner for the mould itself, and then whichever trade fixes the moisture: an electrician or ventilation installer if the exhaust fan is missing, undersized or venting into the roof space rather than outside; a plumber or tiler if water is getting into the wall; a builder if there is a condensation problem in the structure. Cleaning without fixing the cause is a subscription rather than a repair.
When it is someone else
Calling the wrong trade costs an attendance fee to be told so. These are the cases where this problem belongs to someone other than a Cleaner.
the fan is weak, noisy, or discharging into the roof cavity. A fan that vents into a roof space moves the problem rather than solving it, and it is extremely common.
the mould is concentrated at the base of a wall or on the other side of the shower wall. That is water in the structure.
What to do before anyone arrives
- Find out where the exhaust fan discharges. Take the cover off and look, or look in the roof space. Ducted to outside is correct; blowing into the roof cavity is not.
- Check whether the fan actually pulls — hold a sheet of paper to it.
- Note whether the mould is on surfaces only, or whether the plaster behind is soft.
- Look at how the room is used: no window, no fan, long showers and a closed door is a design problem rather than a cleaning one.
What to ask when you book
- Where does the exhaust discharge, and is it ducted to outside?
- Is the fan sized for this room, and is it on a timer or a humidity sensor?
- Is the mould surface-level or has it gone into the plasterboard?
- What is the cause, in your view — ventilation, a leak, or condensation?
What changes the price
No dollar figures here: this directory holds no price data and an invented range is worse than none. What follows is what makes one of these jobs cost more than the same job next door, which is the part you can actually use when comparing quotes.
- Whether anything is being replaced or only cleaned.
- Ducting a fan to outside, especially through a tiled roof or a second storey.
- Whether plasterboard or ceiling lining has to be cut out.
What you can do yourself
Is this licensed work?
Cleaning is not licensed. Installing or ducting an exhaust fan is licensed electrical work. Large-scale mould remediation is specialised work rather than licensed work, and the distinction is worth knowing when comparing quotes.
There is no national register. Search the licence number with the regulator for the state the work is happening in.
- NSWNSW Fair Tradingbuilders, electricians, plumbers and specialist trades
- VICBuilding and Plumbing Commission, and Energy Safe Victoria for electricalbuilding practitioners and plumbers; electricians are Energy Safe Victoria
- QLDQueensland Building and Construction Commission (QBCC)building and most trade contractor licences
- WABuilding and Energybuilders, electricians, plumbers and gas fitters
- SAConsumer and Business Servicesbuilding work contractors and supervisors
- TASConsumer, Building and Occupational Services (CBOS)building and occupational licences
- ACTAccess Canberraconstruction occupations licensing
- NTNT Government building practitioner registrationbuilding practitioners and electrical workers
Licensing thresholds and certificate requirements differ by state and change with amending regulation, so this page describes the mechanism rather than quoting a figure. The regulator’s own page is the current answer.
Common questions
- Who should I hire for mould in a bathroom
- A cleaner for the mould itself, and then whichever trade fixes the moisture: an electrician or ventilation installer if the exhaust fan is missing, undersized or venting into the roof space rather than outside; a plumber or tiler if water is getting into the wall; a builder if there is a condensation problem in the structure. Cleaning without fixing the cause is a subscription rather than a repair.
- Does bleach kill mould?
- It removes the discolouration on a hard surface, which is often all anyone wants, and on a porous surface it does not reach what is below. The more important point is that neither bleach nor anything else stops it coming back if the moisture source is still there — which is why every serious answer to a mould question is a ventilation or leak question.
- Is my exhaust fan meant to vent into the roof?
- No, and a great many do. Discharging humid air into a roof cavity condenses it on the underside of the roof and on the ceiling insulation, which is how a bathroom fan causes ceiling damage in a different room. Ducted to an external vent is the correct arrangement.
Find a Cleaner near you
3,843 cleaners in this directory, ranked on published evidence rather than on advertising.
Who to hire for
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- Who to hire for damp at the bottom of a wallA builder or a damp specialist — but insist on a diagnosis before a treatment. Damp at the base of a wall has …
- Who to hire for an end of lease cleanA cleaning business that does end-of-lease work specifically, and get the agent's own exit checklist first so …
General information about who does what, not advice about your specific job. Licensing, consumer law and council rules differ by state and change; the regulator for your state is the current source. More guides to hiring a tradesperson.