The next step is to remove the remaining mould, and the cleaning solution that should be used differs based on the surface you are cleaning. Dr Heike Neumeister-Kemp, CEO and mycologist at Mycologia, says homeowners should think about the surfaces on which mould is growing before cleaning them. “Group things into non-porous, semi-porous or super porous surfaces. Everything that’s super porous, like wicker baskets, textiles, paper or cardboard, carpet, needs to be chucked. Other things you can try to clean.”
Our experts recommend using ingredients less caustic than bleach, such as diluted vinegar, which causes mould to overeat and then explode, to clear surfaces of mould in the home.
Dr Neumeister-Kemp recommends pouring a concentration of 80% vinegar to 20% water into three buckets, and using the solution and a microfibre cloth to clean mouldy areas. Cloths should be dipped into the first bucket before being used for cleaning a patch of mould. They should then be dipped into the second, then third bucket to ensure cross contamination doesn’t occur. Microfibre cloths, which reach deep into tiny crevices and have a slight electric charge, can be bought cheaply and washed on a hot cycle in the washing machine with vinegar up to 100 times, says Dr Neumeister-Kemp.
Using vinegar may leave streaks on surfaces, so further clean-up of those areas may be required for cosmetic purposes. In this instance, bleach can be used to remove discolouration.
If the mould is on a textile, such as clothing or furniture, there’s a good chance it can’t be completely removed: “As most moulds stain quite badly and also eat into surfaces, if they have grown on fabrics these may be permanently damaged and may need to be thrown out,” says Prof Carter.
Carpets can be particularly problematic for those who have had a mould problem. “You need to replace carpet if there’s been an issue with the carpet getting wet. People [often] don’t remove it, they let it dry out and there are a lot of spores left behind,” says Dr van Nunen.
In most cases, mould can be cleaned up without professional help. However, if mould covers a large area of your home – experts say a rough guide is one metre square – and is dense, or if householders are asthmatic, it’s best to call in the experts.
“If the mould is really bad and extensive it would be a good idea to get professional help. Remember that moulds can give off toxic spores and vapours and if there is a lot of mould this can be dangerous – it can result in hypersensitive or allergic reactions, and asthma and flu-like symptoms,” says Prof Carter. “Areas that have flooded or have had prolonged mould build-up should be cleaned by someone with appropriate equipment, including a HEPA filter vacuum cleaner and proper respirators.”
The cost of professional help varies. An initial investigation can cost around $1500 for an expert to test the site and find the cause of the mould and write a plan for remediation (eradication). After that, it’s a question of the extent of the problem.
“It can range from $2000 to $90,000, depending on the contamination level and size of the property,” says Dr Neumeister-Kemp. “The people who do remediation need to be certified. They need to have the right equipment, special training, a high level of fitness and the ability to sustain thermal stress. They’re not just cleaners. The hourly rate for these people is $80-110.”