What to Do if You Have Mould in Your Home: Your Effective Guide
What Is Mould?
Before you can deal with mould, it helps to understand what it actually is.
Think of mould as nature’s clean-up crew. It’s a type of fungus made up of tiny thread-like roots called mycelium that spread through whatever it’s feeding on. From this base, mould produces fine, fuzzy threads that release millions of microscopic spores into the air, its way of spreading and finding new food sources.
Outdoors, this process is essential. Mould breaks down fallen leaves, trees, and other organic matter, returning nutrients to the soil. Without it, the planet’s recycling system simply wouldn’t work.
But while mould outside plays an important role, mould inside is a very different story.
Why Indoor Mould Is a Silent Threat
Identifying the Cause
You don’t always have to see mould to have a mould problem.
On Waiheke and across much of New Zealand, we live in a humid, coastal environment that provides the perfect breeding ground for mould spores. These spores are everywhere, floating invisibly through the air, waiting for the right conditions to grow: moisture + dust + warmth.
Dust is a major culprit. It’s rich in organic material, and when it builds up, it becomes a buffet for mould and mites. If your home smells musty, or you notice damp spots or condensation, there’s a good chance mould is already active, even if it’s not visible yet.
Professional testing can help identify what types of mould are present and how widespread the problem is. Different species behave differently and can cause different health effects, so lab analysis gives a much clearer picture of what’s really happening.
How to Deal with Mould Properly
Wiping mould away might make it look clean, but it won’t solve the problem.
The first step is always to fix the cause, which is usually excess moisture. That might mean repairing a roof leak, improving ventilation, fixing drainage issues, or managing indoor humidity. Until the moisture problem is resolved, mould will continue to return.
Once the cause is fixed, remediation can begin.
- For mild cases (like window sills or bathroom corners), a natural cleaner such as vinegar can help.
- For more severe infestations, where mould is visible on walls or ceilings, or paint is bubbling, it’s best to call in a professional.
A proper remediation process should include air sampling to measure spore levels and identify mould species. This information helps determine how extensive the problem really is, because sometimes the worst contamination is hiding in rooms that look perfectly fine.
A Real-World Example How to Deal with Mould Properly
We recently worked on a home where mould had been caused by a roof leak. At first, only a few visible patches were noticed. But once we removed the linings, we uncovered widespread Stachybotrys (commonly known as toxic black mould) throughout the walls. Under a UV light, we even found colonies of bacteria glowing neon green on what looked like “dry” timber.
Air testing revealed something surprising. The room with the visible mould actually had fewer spores than the bedrooms and living areas. This showed how far spores can travel through the air and settle in unexpected places.
Before starting the full remediation, we ran dehumidifiers for a week and waited for lab results to confirm contamination levels. This ensured we could approach the cleanup safely and effectively, protecting both the occupants and our team.
We partnered with Clean & Safe Group to carry out the remediation. They fogged the entire house using a natural product called Enzycleanse, which works through an enzymatic process that breaks down the cellular structure of mould spores, completely eradicating them.
The fogging process is applied at around 8 to 9 microns, creating an ultra-fine mist that lingers in the air longer and penetrates walls and substrates. This meant we didn’t have to remove every lining, as the treatment could reach framing and small cavities. It proved to be both cost-effective and highly efficient, far less invasive than the traditional “bash and trash” approach.
Moisture readings indicated a high moisture content in the framing, and further inspection revealed a colony of bacteria on image to the left.
Preventing Mould in the Future
Keeping mould away long-term is all about managing moisture and airflow. Here are a few simple ways to help prevent mould from returning:
- Ventilate daily
Open windows and doors whenever possible to let fresh air flow through your home. In bathrooms and kitchens, use extractor fans while cooking or showering. - Control humidity
If your home feels damp, use a dehumidifier or run a heat pump in dry mode to keep humidity levels below 60%. - Check for leaks
Inspect your roof, gutters, windows, and plumbing regularly. Even small leaks can quickly lead to large mould problems. - Keep surfaces clean and dry
Wipe condensation off windows, especially during winter. Regularly dust and vacuum to remove the organic material mould feeds on. - Let your home breathe
Avoid pushing furniture tightly against cold walls, and make sure wardrobes and storage areas have some airflow.
Small, consistent habits like these can make a big difference in keeping your home healthy and mould-free.
Final Thoughts
Mould is more than just an eyesore, it’s a sign your home’s ecosystem is out of balance.
If you notice a musty smell, condensation, or visible mould, act early. Fix leaks, improve ventilation, and don’t hesitate to call an expert if it looks like more than a surface issue. The sooner you address it, the safer and healthier your home will be.
Before & After - Leaky Roof Renovation
Need help tackling mould in your home?
Get in touch with MJones Building for professional advice and remediation solutions. We are IICRC certified mould remediation specialists.
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