Managing mould after floods and heavy rain 🦠

Our quick science-based guide on how to tackle mould effectively from textiles and other household items.

One gloved hand holding a spray bottle with another gloved hand wiping down a window sill with a white cloth
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Weeks of heavy rainfall and widespread flooding have affected residents across North Queensland. As the severe weather continues there are two constants: mould and questionable mould removal advice on social media. 

Here is our quick guide, based on science and best practices, on how to tackle mould effectively.

Clean Cloth Nappies mould removal advice

There are three main ways to deal with mouldy items:

  1. Completely submerge in a dilute chlorine bleach solution
  2. Clean the surface and wipe it down with chlorine bleach
  3. Seek professional remediation

Before you begin, make sure to wear rubber gloves when handling mouldy items. Add safety goggles and a P2 face mask when cleaning large amounts of mould. 

1. Completely submerge in dilute bleach solution

Submersible textiles can be treated using dilute chlorine bleach (sodium hypochlorite). The easiest way to sanitise them is in your washing machine.

👩‍🔬 Our chlorine bleach sanitise calculator has different dilutions to cover a range of mould growth. We have specific dilutions for non-colourfast items too.

❌ Items not suitable for this method are lined or rubber-backed curtains, foam (cushions) and mattresses. Cushions and mattresses should be replaced.

2. Clean surface and wipe down with chlorine bleach

This option is great for hard surfaces and items that cannot be submerged in water.

If your vacuum cleaner has a HEPA (high-efficiency particulate air) filter, use the vacuum cleaner to remove surface mould. If you do not have a HEPA-filtered vacuum cleaner, wipe surfaces down with clean wet cloths (any fabric) or paper towels first.

🫧 After cleaning the surface, wipe it with diluted chlorine bleach or undiluted 70% ethanol using a fresh cloth or another paper towel.

Use the dilution ratio for general cleaning from your bleach bottle. This is usually a ratio of 1:8. For example, add 125ml of 4.2% bleach to 1L of water.

Tips

  • Do not reuse dirty cloths; rinse them in clean water to avoid cross-contamination.
  • Wash dirty cloths with chlorine bleach or at high heat to kill any mould spores.
  • Do not dry brush or wipe with dry cloths as this could spread the spores.

🌲 Wooden furniture and toys may be salvaged using this method too. If the mould is localised or superficial, the surface of the wood can be sanded to remove the affected timber. The remaining wood can then be wiped down with dilute bleach.

Always follow safe bleach practices. Do not mix chlorine bleach with other chemicals.

3. Seek professional remediation

Mould on plasterboard (Gyprock), floorboards and load-bearing structures should be assessed by professionals, especially if they have been wet for more than two days.

Mould that is superficial and only on the painted layer can be removed with method 2 above.

🏠 If your house was flooded, dry out the areas thoroughly using fans and heating mats while you await professional remediation (if applicable). Ensure the area is completely dry before new plasterboard is installed.

🔑 In most cases, home insurance does not cover mould damage or mould removal. However, you may be able to make a claim if mould is part of an insured event (for example, from storm damage or flooding).

Frequently asked questions (FAQs)

What about using white vinegar, tea tree oil and clove oil to kill mould?

Vinegar only kills one strain of mould and is not broad-spectrum like chlorine bleach. Tea tree oil and clove oil require high concentrations to be effective, which makes them very expensive and not practical options. Most solutions recommended are too diluted to be effective. Their bottles also don’t usually list their concentrations, making them hard to dilute properly.
Are there other products I can use?

Commercially sold mould removal products are usually effective, although most of them contain sodium hypochlorite (chlorine bleach) anyway.
What kind of bleach do I need?

Any brand of chlorine bleach is fine, including the supermarket’s own brand.
What constitutes a hard surface?

Surfaces that are non-porous such as countertops, tiles, glass, sealed surfaces, and some plastics. Assess painted and varnished items to see if the mould has penetrated underneath the surface.
How can I prevent the mould from returning? This feels like a losing battle!

Mould is very opportunistic and will grow whenever the conditions are right: in damp, warm and dark environments. Ensure good ventilation and airflow around the house, and reduce humidity where possible to discourage mould growth.