We’ve all heard and perhaps lived the horror stories: dark spots appearing on your ceiling, flat-pack furniture literally rotting away, that musty smell, mouldappearing on your clothes and shoes, and even sickness or respiratory issues.
Mould is a fungus that thrives in damp areas either inside or outside.
Dr Caroline Halley, a senior research fellow at the University of Otago’s School of Medicine and Health Sciences, explains that mould needs “something to grow on, a source of nutrients and a supply of moisture” to flourish.
“Since mould can grow on many substrates and can absorb nutrients from small quantities of dust, the most important and modifiable factor to reduce indoor mould is to control moisture,” Halley says, adding that it can be difficult to do this in this country because our climate is so damp.
“New Zealand has a pretty bad residential mould and dampness problem,” she notes, pointing to recent Census statistics that show about 15 per cent of the country often or always have mould patches bigger than an A4 size of paper in their homes.
In fact, one in five houses in New Zealand are damp, due to “housing standards that have not previously focused on making homes healthy”, Halley says.
Mould can appear in all sorts of colours, from green to grey, brown and red, or black and white, or as stains on smooth surfaces. It’s normal for small amounts to appear in our homes, but it can cause serious issues when left to grow, signalling that there’s too much moisture in the air or maybe even a leak somewhere.
The most common cause of mould is condensation created when warm, damp air from your kitchen or bathroom comes into contact with cold surfaces.
Mould grows when moisture levels are too high inside our homes. Photo / 123rf
How does mould affect us?
Mould doesn’t just damage your home, furniture and clothes - it can also harm your health.
It releases tiny, invisible spores into the air which can cause serious health problems when you breathe them in. Elderly people, young children, and those with allergies or breathing problems are particularly at risk. Some mould spores can even be life-threatening when inhaled.
A study carried out by the University of Otago from 2010 to 2014 looked at 450 homes in Wellington, and found that high levels of visible mould, mould odour and leaks were all associated with new onset wheezing in young children.
“Most of the adverse health associations that have been found to be strongly associated with dampness and mould are respiratory - so that’s increased cough, wheeze, more respiratory infections, increased asthma symptoms, and worryingly, the development of asthma in young children,” says Halley.
According to Allergy NZ, all moulds can potentially cause health issues, especially if you have asthma or another respiratory condition.
Some people are even allergic to mould, causing their immune systems to react when coming into contact with it. The symptoms for a mould allergy are similar to cough and cold symptoms, as well as having itchy or watery eyes, nose and throat.
If you suspect you’ve got a mould allergy or infection, see your doctor.
A mould allergy can cause cold-like symptoms as well as itchy eyes or a runny nose. Photo / 123rf
How do you get rid of mould?
There are all kinds of products on the supermarket shelf promising to kill the mould in your home, but the best way to get rid of it might be good old-fashioned white vinegar, according to an online home care resource from Kāinga Ora.
Don’t use it on surfaces you don’t want to risk discolouring, as white vinegar can cause bleaching.
Pop some white vinegar into a spray bottle and apply directly to mould, or wipe it onto the surface with a clean cloth. To avoid damaging the paint on your walls or windowsills, you can dilute the vinegar with an equal amount of water and leave it on the surface for a few days. Then wipe off the mould with a clean cloth soaked in soap and water.
Either wash or throw away the cloth when you’ve finished to avoid spreading the mould.
How do you prevent mould growing?
So, we know how to get rid of it - but how do we stop mould from growing in the first place? The key is to heat and ventilate our homes properly.
“Even ventilating for 10 minutes a day can help us reduce that build-up of moisture, especially if we can do this when our houses are warm,” Halley says.
“We need to make sure we also ventilate when we’re carrying out household activities that can generate moisture, such as using extractor fans when we are showering or cooking, using a clothes dryer or not drying our clothes inside without ventilating, not using unflued gas heaters.
“Making sure we fix up leaks as soon as we can and also making our houses easier to heat by installing insulation can also help. If mould is building up in your home, try and remove it frequently, particularly in bedrooms where we spend a lot of our time.”
But she notes that it doesn’t just fall to tenants and homeowners to deal with the issue of mould - it’s a country-wide problem that needs fixing.
“As a country we also need to start building our houses so that they are less likely to grow mould - this means making changes to our building code, to make sure we build our healthy homes from the start.”
Tips to mould-proof your home
Open windows for a couple of hours each day, or longer on sunny days
Open windows or use an extractor fan in bathrooms
Hang washing outside or near a window, or use a vented dryer
Keep lids on pots when cooking, use an extractor fan or open kitchen windows
Keep kitchen and bathroom bench areas and floors dry
Check areas like taps and drains for leaks and get them fixed
If using a portable gas heater, crack a window
Bethany Reitsma is an Auckland-based journalist covering lifestyle and entertainment stories who joined the Herald in 2019. She specialises in lifestyle human interest stories, foodie hacks (what can’t you air fry?!) and anything even remotely related to coffee.
