The best ways to get rid of mould in your home

Floods, heavy rains and humidity are creating the perfect storm for mould and mildew to grow in our homes. For some, it’s a minor inconvenience that requires a bit of time and effort to fix. For others, it can escalate to levels that call for expert intervention.

Before you reach for the bleach, it’s best to hit pause and assess the source, type and extent of mould growth. Also, you should take time to learn more about the effects of mould on your health, and what to do to prevent it from becoming a problem in the long term.

What is mould and how does it form?

Given the climate in Australia and where our homes are built, it’s fair to say that our households are particularly prone to unwanted mould growth. The World Health Organisation estimates that dampness affects 10–50 per cent of our indoor environments, with the problem being most severe near rivers and on the coast.

Indoor environmental health consultant Lucinda Curran says “mould plays a very important role in the environment, and its spores are everywhere”.

“Spores can lay dormant for a long time and, when the conditions are right, become active,” she says. “Usually what they’re waiting for are the right levels of moisture.”

Curran says there’s a huge focus on the devastating effects of “black mould,” but “people can be sensitised to other types of mould as well”.

Even if you can’t see visible signs of water damage or mould, Curran suggests you get it checked out.

“A common myth about mould is that unless you can see it or smell it, there isn’t any,” she says. “This couldn’t be further from the truth! 

“You can smell some types of mould because they release microbial volatile organic compounds [mVOCs] or because of the bacteria present in them. Some, however, are odourless.

“Also, not only are many types of mould invisible to the naked eye, but they’re active within wall cavities and other interstitial spaces. This is often referred to as ‘hidden mould’.”

What are the health effects of mould?

A growing body of evidence tells us that humans can get sick from exposure to home-based toxins. Allergies, asthma and a condition known as Chronic Inflammatory Response Syndrome (CIRS) have all, at times, been linked to the mould lurking in water-damaged buildings.

“Some moulds have known adverse health effects,” Curran says, “whereas others may only cause health effects in someone who is sensitive or sensitised to them.

“This often occurs through repeated exposure,” she adds. “For instance, [when] living or working in a mouldy environment, eventually the person can begin to react to that particular genus or species of mould.” 

Curran emphasises that whatever the source and extent of mould exposure, “cleaning and removal needs to be much more thorough for someone who is sensitive”.

What works to get rid of mould?

Unfortunately, bleach-based products are a stop-gap measure that won’t kill mould permanently. At best, bleach will partially whiten discoloured areas. At worst it can damage surfaces and have adverse health effects.

Vinegar is often hailed as a non-toxic alternative. But does it really work on mould, or should we save it for the salad dressing? 

For Curran, vinegar is not the cure-all some think it is. She says that when it comes to cleaning mould, it’s the technique rather than the product that we should be focusing on.

To make sure the problem is eradicated entirely you need to identify the source of the problem and eliminate it.

“Once the cause of the moisture has been resolved, materials need to be dried out, and then cleaning (or replacing affected materials) can take place,” Curran explains. “Simple things like vacuuming with a HEPA filter installed, using a scrubbing brush, [single-use] microfibre cloths and soapy water can all help.

“I often recommend adding essential oils to the soapy water mix to ‘supercharge’ the effect. Oregano and thyme have been shown to be excellent at killing mould.”

How to stop mould from returning

Jeanette Williams of Building Biology Sydney believes there are several ways to set your home up for a mould-free future.

Even if you have escaped flooding or rain, “when relative humidity is over 70 per cent the chance of mould growing on your furniture and possessions is still very high”, Williams says. 

“Rooms with poor ventilation, low sunlight levels and especially those that are overcrowded are more prone to develop mould,” she adds.

 According to Williams, there are several steps you can take to reduce the risk:

• Keep gutters and drains clear of leaf litter and ensure that water drains away to stormwater rather than the ground.
• Maintain a gap between garden beds and your foundations.  
• Use a dehumidifier, set your airconditioner to dry mode and/or run ceiling fans to help to move air.  
• Mould also feeds on dust mites, so decluttering and regular dusting are a must. 
• Full-house ventilation systems are a great way to reduce internal humidity levels and promote cross ventilation and should be considered for all new builds and renovations.
• Take measures (with expert help, if necessary) to dry out affected carpets, surfaces, walls and ceilings, remembering that porous materials need special attention.  

Who’s responsible for cleaning and removing mould in a rental property?

According to Jo Natoli, a property manager and principal at The Rental Specialists, mould can be a particularly problematic issue in rental properties. Ultimately, both landlords and tenants share some of the responsibility. 

A landlord is required to offer a property that’s “fit for habitation, in a reasonable state of repair and clean”, Natoli says. And “if mould is caused by a leak in a roof, or by a leaking pipe or gutters or some other fault with the property, the landlord is responsible for fixing the fault and making good any damage”. 

“Also, a landlord has to inform the property manager if there’s been a history of problems in a property that could pose a significant health risk,” she adds.  

A tenant has a duty to keep the property clean and ventilated and take reasonable steps to prohibit the growth of mould. So, for example, Natoli says, “If the tenant has caused the mould, by not regularly cleaning or ventilating the home, or by allowing carpets to get and stay wet, they can be held responsible for cleaning and making good the damage.”