How to clean mould from walls, furniture after a flood and avoid a serious health hazard

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As floodwaters recede from hundreds of homes across Queensland and New South Wales and the clean-up begins, pathogens and mould are becoming a serious health hazard.

Experts are warning flood-affected residents and thousands of volunteer Mud Army cleaners to take care when handling contaminated items, and not rush to get back into flooded homes.

Gerard Murtagh launched mould remediation business MouldMen after enduring the catastrophic 2011 Brisbane floods.

"We were all part of the Mud Army and I realised there was a need for cost-effective mould remediation," he said.

"Obviously the insurance companies were as busy as they could be, and there were so many people out there who were affected by mould but couldn’t get rid of it."

Fast-forward a decade, and Mr Murtagh is now watching Queensland’s unfolding flood disaster with concern.

"I was watching the news the other night and I was having a cold sweat because I was seeing all these people with no shoes on, no gloves on, just pushing away the mud," he said.

"That is the probably more dangerous right now than the actual mould growth. The pathogens and all the nasties in that mud are from faeces and dead animals and silt and all these other things that can make you very sick."

WorkSafe Queensland warns that people exposed to mould can suffer irritation of the eyes, nose, throat and skin, asthma flare-up, hayfever symptoms, infections, and even hypersensitivity pneumonitis, a rare disease where lungs become inflamed due to an allergic reaction..

If you have been directly impacted by the floods, you may be eligible for these government grants.

Mr Murtagh said anyone participating in the Mud Army 2.0 clean-up should ensure they are wearing full personal protective equipment, including gumboots, gloves, and a mask "to ensure you aren’t breathing in those harmful pathogens from muddy water".

And once clean-up inside a house begins, the first step is documenting everything you own; taking photos, videos and notes to ensure your insurance claims can be made accurately.

“Then you can start removing everything out of the house. Anything that is a soft furnishing that has been touched by floodwaters needs to go and put out on the street for collection,” Mr Murtagh said.

That includes carpet, floor underlays, mattresses, cushions, couches. Anything that has touched floodwater must be ripped out and discarded safely.

But Mr Murtagh warns the clean-up must go deeper than just furniture.

"We’ve been dealing with a lot of different people over the past couple of days who were like, 'Yes we got rid of the water and we mopped the floors, and went back in our home'," he said.

"And I had to say to them, 'I'm really sorry but that plaster that you’ve got in the wall cavities is full of pathogens and full of water, and that will go mouldy and you can’t leave it there'."

Plasterboard in flooded homes must be cut out about 50 centimetres above the waterline and removed, and wall insulation that could be storing pathogens and damp must also be taken out.

Timber or metal studs can be pressure-washed, sprayed with antimicrobial disinfectant, and left to dry completely.

"I know that that’s going to mean you’ll have power points that you’ll have to look after; you’re going to have plaster that’s going to need to be replaced," Mr Murtagh said.

"But this is the safest way for people to go back into their homes knowing they’re not going to be moving into a home that’s got wall cavities full of pathogens and potentially mould growth."

For people hoping to salvage some of their more costly soft furnishings, such as couches or mattresses, Mr Murtagh says the long-term cost isn’t worth it.

"The harm that you’re going to do by having these items back in your home and potentially sleeping on them, like a mattress, it could be devastating to your health," he said.

Hardwood furnishings such as tables may be saved with thorough scrubbing using hot soapy water with antimicrobial disinfectant, or normal disinfectant to wipe mould away from the surface of antiques.

And if you usually turn to bleach to eradicate mould, Mr Murtagh said it was a waste of time.

"Bleach doesn't kill mould, it actually just discolours the mould and makes the surface look clean," he said.

While mould removalists are likely to be booked out for weeks, Mr Murtagh said residents could tackle mould extermination themselves – but if they find any mould bigger than their hand, a professional will need to be called in.

"If it’s bigger than [your hand] it means the mould growth has a constant source of moisture and it’s now spreading across the ceiling or across the walls," he said.

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