mouldcleaning.com.au

The whole house

When should you call a professional about mould?

The pages do not stop a householder at a symptom; they stop at conditions, and this page sets out the ones each kind of source names: the size WA Health calls complex, the mould that returns after cleaning, mould that is bound up with the structure, a home that has taken flood water, and the people whom the health pages ask to stay out of the room.

General information from official health, building and housing sources, not advice about your home, your health or your tenancy. The page behind most of this one is Guidelines for managing mould and dampness related public health risks in buildings, from WA Health.

Water from a leaking roof, reaching the ceiling: NSW Health lists a leaking roof and a blocked rain gutter among the water leaks and plumbing problems to repair.Water from a gutter fault, into the top of the outside wall: Consumer Protection WA’s list of what a landlord should do to avoid mould developing includes cleaning and maintaining the gutters, so rainwater stays out of the roof cavity.Where a roof or ceiling leak shows: NSW Fair Trading’s own inspection list says to check for damp or mould along skirting boards, walls and ceilings.Where a gutter fault shows: a discoloured or bulging patch that may be cold or damp to touch, in the wall or roof cavity (Consumer Protection WA). Shower steam, and the bathroom exhaust fan the building code sizes: the 2025 National Construction Code sets a minimum exhaust flow rate, 25 litres a second for a bathroom or sanitary compartment.Signs in a wet area: the SA Government’s inspection list says to look for mouldy walls, lifting tiles, peeling paint or pools of water. Moist air reaching cold window glass: the national home design guide says condensation forms when humid air meets a cooler surface, such as a window in winter.Condensation and mould on the window: the national home design guide says aluminium frames form a thermal bridge into the home and are prone to condensation.Moist air reaching the outside wall behind a wardrobe: one of Homes Tasmania’s tips for a dry, well-aired home is to allow space between furniture and the wall so air can flow, and it calls this very important with wardrobes.Mould on the outside wall behind the wardrobe: one of Homes Tasmania’s tips is not to stack boxes or other items against outside walls, especially walls that do not get a lot of sun.A small patch on a bedroom wall: NSW Health says it is good to remove mould as soon as it appears. Water from a concealed pipe leak, down inside the wall: SA Water says damp, warped or discoloured walls, floors or carpets can suggest a concealed leak indoors.Where a concealed leak shows: Icon Water says to look in the kitchen, bathrooms and laundry for dripping taps, washing machine and dishwasher connections, and damp patches on the walls. Flood water in the home (the line marks no depth): Victoria’s health department says flooding can cause excessive mould growth, which has to be cleaned up before moving back in.A floor joist with staining or decay: the Queensland timber guide says a surface stain that scrapes off to sound timber underneath is not of concern, while wood that is soft and spongy or easily penetrated has decayed. Damp rising from the ground into the base of the wall: NSW Health says rising damp is ground moisture rising up a brick or stone wall.Where rising damp shows: the base of the wall and the skirting, where Consumer Affairs Victoria says damp brick walls can indicate rising damp or salt damp.Damp ground under the floor: Homes NSW says rising damp is moisture from the ground travelling up into a home through the bricks or stone in its walls.A damp subfloor: NSW Fair Trading’s inspection list says to lift carpet and check for rotting floorboards or damp. Water from a leaking roof, reaching the ceiling: NSW Health lists a leaking roof and a blocked rain gutter among the water leaks and plumbing problems to repair.Water from a gutter fault, into the top of the outside wall: Consumer Protection WA’s list of what a landlord should do to avoid mould developing includes cleaning and maintaining the gutters, so rainwater stays out of the roof cavity.Where a roof or ceiling leak shows: NSW Fair Trading’s own inspection list says to check for damp or mould along skirting boards, walls and ceilings.Where a gutter fault shows: a discoloured or bulging patch that may be cold or damp to touch, in the wall or roof cavity (Consumer Protection WA). Shower steam, and the bathroom exhaust fan the building code sizes: the 2025 National Construction Code sets a minimum exhaust flow rate, 25 litres a second for a bathroom or sanitary compartment.Signs in a wet area: the SA Government’s inspection list says to look for mouldy walls, lifting tiles, peeling paint or pools of water. Moist air reaching cold window glass: the national home design guide says condensation forms when humid air meets a cooler surface, such as a window in winter.Condensation and mould on the window: the national home design guide says aluminium frames form a thermal bridge into the home and are prone to condensation.Moist air reaching the outside wall behind a wardrobe: one of Homes Tasmania’s tips for a dry, well-aired home is to allow space between furniture and the wall so air can flow, and it calls this very important with wardrobes.Mould on the outside wall behind the wardrobe: one of Homes Tasmania’s tips is not to stack boxes or other items against outside walls, especially walls that do not get a lot of sun.A small patch on a bedroom wall: NSW Health says it is good to remove mould as soon as it appears. Water from a concealed pipe leak, down inside the wall: SA Water says damp, warped or discoloured walls, floors or carpets can suggest a concealed leak indoors.Where a concealed leak shows: Icon Water says to look in the kitchen, bathrooms and laundry for dripping taps, washing machine and dishwasher connections, and damp patches on the walls. Flood water in the home (the line marks no depth): Victoria’s health department says flooding can cause excessive mould growth, which has to be cleaned up before moving back in.A floor joist with staining or decay: the Queensland timber guide says a surface stain that scrapes off to sound timber underneath is not of concern, while wood that is soft and spongy or easily penetrated has decayed. Damp rising from the ground into the base of the wall: NSW Health says rising damp is ground moisture rising up a brick or stone wall.Where rising damp shows: the base of the wall and the skirting, where Consumer Affairs Victoria says damp brick walls can indicate rising damp or salt damp.Damp ground under the floor: Homes NSW says rising damp is moisture from the ground travelling up into a home through the bricks or stone in its walls.A damp subfloor: NSW Fair Trading’s inspection list says to lift carpet and check for rotting floorboards or damp. The whole houseSee the house

The stop conditions, side by side

Each row is one condition, and each column one kind of source: a health department, a tenancy regulator, or a building commission. Where a kind of source does not name that condition, the cell says so.

When the official pages say to stop, by kind of source
ConditionHealth pagesTenancy pagesBuilding pages
SizeOne square metre is WA Health’s mark: contamination no greater than that is part of its definition of a simple problem, and anything larger, or found in more than one room, is complex. The same guidelines call the figure a recommendation rather than a health threshold. No source here says.No source here says.
Mould that returnsWA Health’s guidance says a recurring problem may still be simple to clean, but that it shows the source has not been addressed, and professional help may be needed to identify it; its public page on mould and dampness reaches the same point, saying professional help may be needed where a problem is large, keeps coming back or cannot be found. Consumer Protection WA says a mould problem that covers a large area, or that keeps coming back, should be treated by a mould removal professional, in both its tenants and its landlords bulletins. In Victoria, mould or damp caused by or related to the building structure that makes the property unsafe or insecure is an urgent repair. No source here says.
In the structureWA Health’s guidelines make a problem complex where its causes are faults in building design or structure, or are difficult to repair, and where mould is confirmed or suspected in the air conditioning system, apart from low-level growth inside a single split system. Queensland’s minimum housing standards require the walls, ceiling and roof to be in good condition and not affected by significant dampness, and repairs needed to bring a property back to the standards are classified as emergency repairs, though emergency repairs do not apply to rooming accommodation. Victoria’s minimum standards require all rooms to be free from mould and damp caused by or related to the building structure. The Queensland building commission’s guide expects most lining products that were inundated to be replaced, and any bulk wall or ceiling insulation that was under water to be removed and replaced as part of the repair. In houses built after about the mid 1970s the lining may also be the wall bracing, so where it is stripped the same guide says temporary diagonal timber braces should be nailed to each wall until permanent bracing and lining go back.
After a floodWA Health’s indoor mould guidance says that where flood water has affected a space for more than 24 to 48 hours, anyone entering should assume extensive growth and a risk of complex mould, and wear protection suited to a complex clean-up, and that a home where flood water has left mould growing will likely prove complex. Victoria’s health department lists the people who should stay away while a flood-damaged home is cleaned or repaired: children under 12, babies especially; women who are pregnant; anyone over 65; and people whose immune systems are weakened or who live with allergies, severe asthma or a lung disease. NSW’s flood guidance says a property owner is more likely to be responsible for clean-up and repairs, that a tenants’ strata scheme may carry some repairs in a strata-managed property, and that renters should contact their property manager or landlord. Queensland’s tenancy authority is direct about natural disasters: where mould is caused by one, the property manager or owner is responsible for addressing it. The Queensland building commission’s assessment order for a flood-damaged house is: a licensed electrician’s electrical safety inspection before any assessment or repair begins, a plumbing safety inspection by an appropriately licensed person, and a structural inspection by someone competent for the task, such as a registered structural engineer, a building certifier or a licensed builder.
HealthVictoria’s health department says some people should not remove mould or be in the room while it is removed: pregnant women, children, and anyone with a weakened immune system or a chronic lung disease. NSW Health names the same people as more sensitive or more at risk: people with asthma, allergies or other breathing conditions, and anyone with a weakened immune system, or a chronic lung disease, who is more at risk of a mould infection, particularly in the lungs. Victoria’s renting rules give a renter a way to show the mould is an urgent repair: proof that it is dangerous, with a doctor’s report for people with an existing health issue such as asthma given as the example. No source here says.

Which professional for which problem

  • Different trades for different causes. WA Health’s guidance lists the professionals that a mould problem can call for, whether to track it down and clean it or to put the underlying cause right: plumbers for plumbing leaks, builders or roof specialists for leaks in the building structure, and air-conditioning consultants or engineers for problems with the air conditioning system. For rising or lateral damp, NSW Health names an experienced building consultant, who can check the damp course and recommend ways to fix the problem.
  • For testing and assessment, the name to know is the occupational hygienist. NSW Health says that if you think you have mould but cannot find the source, you could employ one, who can run specialist mould tests and give advice for a fee. Victoria’s health department names the same profession for the same case and points to the Australian Institute of Occupational Hygienists. WA Health’s guidelines widen the field: building maintenance staff with training, mould assessors and remediators, building consultants, Indoor Environmental Quality assessors, and local government environmental health officers.
  • NSW Health says that since most mould is visible it is generally not necessary to test for mould in the home, though some contamination may sit in cavities or the ceiling. WA Health does not recommend sampling spores from a surface or the air as a way to set the level of health risk, and Tasmania’s health department does not recommend testing, since mould is found everywhere and there are no health guidelines to measure results against.
  • WA Health’s guidelines state that no formal Australian qualification certifies a mould assessor, and ask a householder to establish a professional’s level of expertise and competence before engaging them, including by sighting qualifications or previous work. Where the work needs a licence or registration, Victoria’s repairs page says the renter or rental provider must use a qualified person.
  • Where a professional is engaged, the check on the work matters too. WA Health says to check a professional’s experience and track record before engaging them to remove mould, and its guidelines encourage a post-remediation evaluation, add that it should not be carried out by the same entity that did the remediation because of the conflict of interest, and note that no legal requirement attaches to either.

If you rent

In Victoria, renters may need to give their rental provider proof that the mould is dangerous and needs urgent repair, and the page’s example is a doctor’s report for people with an existing health issue like asthma. The same page adds that renters may be able to get rental providers to pay them back for any health assessment or medical report by applying to VCAT.

Where the dispute is about who caused the mould rather than how urgent it is, the tenancy authority for each state sets out its own process, and the renting guide keeps them side by side.

If the building might contain asbestos

The Queensland building commission’s guide to flood-damaged timber names the trade for sheeting that may contain it, and advises: do not sand or cut those products, and leave their removal and disposal to a specially licensed (Class B) contractor. The federal safety agency’s advice for householders is plain: it is not recommended that you handle or remove asbestos yourself, and in some places the law goes further: in the Australian Capital Territory any removal needs a licensed removalist, unless it is part of minor routine maintenance or other minor work, and in Queensland only a removalist holding a Class A licence may remove friable material. The agency adds that a professional is easier, safer and often cheaper, and that the waste has to be disposed of at a landfill that is licensed to take it. WA Health’s page on environmental health after cyclones and floods adds its own order for damaged material on a site: identifying it is the first priority, followed by controlling access to it and any disturbance of it.