If you've noticed dark patches creeping across your walls or ceiling, you know that sinking feeling. Mould doesn't just look bad — it can affect your family's health, especially if you have young children or anyone with asthma at home. The good news? You can tackle most household mould yourself with supplies from Coles or Bunnings.
**Quick Answer:** To remove mould from walls and ceilings, spray white vinegar (4 parts vinegar to 1 part water) onto the affected area, leave it for one hour, then wipe clean with a damp microfibre cloth. For non-porous surfaces like bathroom tiles, use diluted bleach (250 ml per 4 litres of water). Always wear a P2 mask and gloves, and never mix bleach with vinegar.
Why Mould on Your Walls Is More Than a Cosmetic Problem
Mould releases tiny spores and mycotoxins into the air you breathe. According to [CSIRO scientist Anthony Wright](https://www.csiro.au/en/news/all/articles/2020/august/dealing-with-mouldy-houses), mould "releases toxic chemicals, called mycotoxins, which can cause allergic reactions for some people."
For families with children, the stakes are higher. A [2022 review by Queensland University of Technology researchers Coulburn and Miller](https://pmc.ncbi.nlm.nih.gov/articles/PMC8835129/) found that **7.9% of childhood asthma in Australia is attributable to indoor dampness**. With 1 in 9 Australians living with asthma, keeping mould under control isn't just about appearances — it's about breathing easier.
The frustrating truth? "A mould problem is always a moisture problem." Cleaning the mould is step one. Preventing it means finding and fixing the moisture source — whether that's a leaky pipe, poor ventilation, or condensation from your morning shower. If you're dealing with [hard water buildup](/cleaning-101/bathroom/is-hard-water-affecting-your-home-health) at the same time, excess moisture may be a bigger issue than you realise.
Before You Start: Essential Safety Steps
Before you reach for any cleaning product, protect yourself. Mould spores become airborne when disturbed, and the wrong approach can make things worse.
What You'll Need
**P2 face mask** (not a cloth or surgical mask — only P2 or N95 rated masks [filter mould spores effectively](https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/mould-and-your-health))
**Rubber gloves** (PVC or nitrile)
**Safety glasses** or goggles
**Microfibre cloths** (several — swap to a clean one frequently)
**Good ventilation** — open windows and doors before you start
Who Should Not Clean Mould
**⚠️ Safety note:** The [Victorian Department of Health advises](https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/mould-and-your-health) that pregnant women, children, and people with weakened immune systems or chronic lung conditions should not remove mould or be present during removal. [Asthma Australia recommends](https://asthma.org.au/triggers/flooding-and-mould/) asking someone without asthma to do the cleaning if possible.
The One Rule You Must Follow
**⚠️ Safety note:** **Never mix bleach and vinegar.** This combination produces toxic chlorine gas, which can cause severe respiratory distress. If you're switching between methods, rinse the surface thoroughly with plain water first. — [NSW Health](https://www.health.nsw.gov.au/environment/factsheets/Pages/mould.aspx)
Method 1: White Vinegar (Best for Painted Walls and Ceilings)
If your mould is on painted walls, plasterboard, or ceilings — which it usually is — **vinegar is your best option**. Bleach cannot penetrate porous surfaces. It removes the visible colour but leaves the roots alive underneath, often making the problem worse over time.
Vinegar's acetic acid works differently. It penetrates the surface to kill mould at its roots. A [peer-reviewed study from the University of Adelaide](https://pmc.ncbi.nlm.nih.gov/articles/PMC4483703/) found that household vinegar (4–5% acetic acid) effectively inhibits common household mould species like *Penicillium chrysogenum*, though it has limited effect on some less common species.
What You'll Need
White distilled vinegar (available at Coles or Woolworths)
Spray bottle
Clean microfibre cloths (at least three)
Scrubbing brush with firm bristles
Bucket of clean water
Ladder (for ceilings and high walls)
Steps
**Fill your spray bottle** with a solution of 4 parts vinegar to 1 part water, as [recommended by NSW Health](https://www.health.nsw.gov.au/environment/factsheets/Pages/mould.aspx). For stubborn mould, many cleaning professionals use it undiluted.
**Spray generously** over the entire mouldy area, extending a few centimetres beyond the visible edges. Mould roots spread further than what you can see.
**Leave it for at least one hour.** This contact time allows the acetic acid to penetrate and kill the mould. Don't be tempted to rush this step.
**Wipe the surface** with a damp microfibre cloth using firm, even strokes. Work in one direction to avoid spreading spores. **Swap to a clean cloth frequently** — you can't clean properly with a dirty one.
**For stubborn patches**, use a scrubbing brush with firm bristles. Apply more vinegar as you go.
**Dry the area** by pressing a clean, dry cloth against the surface. Open windows to let fresh air circulate.
**Tip:** To help prevent regrowth, spray vinegar on mould-prone areas — ceiling corners, behind furniture, around windows — once a fortnight. This works best alongside proper ventilation, not as a substitute for it.
For more ways to use vinegar and other natural ingredients around the home, see our guide to [natural cleaning solutions](/cleaning-101/sustainability/green-cleaning-101-how-to-make-use-natural-cleaning-solutions).
Method 2: Diluted Bleach (Best for Non-Porous Surfaces)
Bleach works well on **non-porous surfaces** like ceramic tiles, glass, porcelain, and sealed stone. On these materials, it kills mould on contact and provides short-term protection against regrowth.
On painted walls, plasterboard, wood, or grout, bleach is less effective. The [US Environmental Protection Agency does not recommend bleach](https://www.epa.gov/mold) as a routine mould cleanup method because it cannot penetrate porous materials. For those surfaces, use vinegar (Method 1) instead.
What You'll Need
Chlorine bleach (standard household bleach)
Bucket
Clean cloths
Rubber gloves, P2 mask, and safety glasses
Ladder (if needed)
Steps
**Mix your solution:** Add 250 ml of bleach to 4 litres of water, as [recommended by NSW Health](https://www.health.nsw.gov.au/environment/factsheets/Pages/mould.aspx). Work in a well-ventilated area with windows open.
**Dip a cloth** into the solution and wring it out so it's damp, not dripping.
**Wipe the mouldy area** using firm, even strokes. For hard-to-reach spots — around taps, in tile grout lines — an old toothbrush works well.
**Re-dip and repeat** until all visible mould is gone. If the solution gets murky, make a fresh batch.
**Do not rinse with plain water.** The residual bleach helps prevent regrowth on non-porous surfaces.
**Blot dry** with a clean cloth and keep the area ventilated for at least an hour.
**⚠️ Safety note:** Never use bleach in an enclosed space without ventilation. Bleach fumes can irritate your eyes, skin, and respiratory system. If you feel dizzy or short of breath, leave the area immediately and get fresh air.
What You Might Have Tried That Didn't Quite Work
If you've been battling mould for a while, you've probably already tried a few things. You're not doing anything wrong — some popular approaches just don't work as well as people think.
**Dry brushing mould off the wall** seems logical, but it sends thousands of spores into the air. [Better Health Channel Victoria](https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/mould-and-your-health) specifically warns against this — always wet the mould first.
**Spraying a commercial mould remover once and walking away** may lighten the stain, but many products don't address the roots. Without ongoing moisture control, the mould returns within weeks.
**Bleaching painted walls repeatedly** can actually make things worse. The water in bleach solution (bleach is 90–95% water) feeds the mould roots beneath porous surfaces, while only the surface colour disappears.
The key insight is simple: **match your method to your surface**, and always address the moisture behind the mould.
When to Call a Professional
DIY mould removal works well for small patches. But there are times when professional help is the smarter choice.
**Consider calling a professional if:**
The mouldy area is **larger than 1 square metre** (roughly the size of a bath towel). Cleaning large areas without containment can spread spores throughout your home.
Mould keeps returning **despite cleaning and improving ventilation**. This usually signals a hidden moisture source — a leaking pipe behind the wall, rising damp, or poor drainage.
You can see mould **inside wall cavities, under flooring, or in ceiling spaces**. Structural mould needs specialist equipment and containment.
Anyone in your household has **asthma, allergies, or a compromised immune system** and is reacting to the mould.
Research from [CSIRO](https://www.csiro.au/en/news/all/articles/2020/august/dealing-with-mouldy-houses) suggests that eradicating mould and damp in Australian housing could cut health expenditure significantly — making professional assessment an investment that pays off.
How to Stop Mould from Coming Back
Removing mould is only half the job. Preventing it means tackling the moisture source.
Ventilation
**Run your bathroom exhaust fan** for at least 30 minutes after every shower. Make sure it vents outside — not into the ceiling cavity, which is a [common installation error flagged by CSIRO](https://www.csiro.au/en/news/all/articles/2020/august/dealing-with-mouldy-houses).
**Open windows daily**, even for 15–20 minutes, to create cross-ventilation.
**Use exhaust fans when cooking** and when using the clothes dryer indoors.
Humidity Control
Keep indoor humidity below **60%** (ideally 40–50%). A basic hygrometer from Bunnings costs around $15.
**Use a dehumidifier** in damp-prone rooms during winter and in humid climates.
Moisture Sources
Repair leaking taps, pipes, and roof areas promptly.
Clear gutters and downpipes to prevent water pooling near walls.
Check window seals and replace cracked or missing caulking.
Ongoing Maintenance
Spray mould-prone areas with white vinegar once a fortnight. Wipe down [bathroom surfaces](/cleaning-101/bathroom/8-bathroom-cleaning-hacks-that-will-save-you-time-and-money) after showers. Move furniture a few centimetres away from exterior walls to allow air circulation.
Frequently Asked Questions
Q: Does bleach actually kill mould on walls?
Bleach kills mould on non-porous surfaces like tiles and glass. On painted walls and plasterboard, it only removes the visible colour — the roots survive beneath the surface. White vinegar is more effective on porous materials because its acetic acid can penetrate the surface.
Q: Is mould in a rental the tenant's or landlord's responsibility?
In most Australian states, landlords are responsible for structural issues causing mould (leaks, poor ventilation, rising damp). Tenants are expected to take reasonable steps like using exhaust fans and wiping down wet surfaces. If mould persists despite your efforts, contact your landlord or agent in writing.
Q: How do I know if mould is dangerous?
All indoor mould should be removed when found. [The Australian Government's enHealth guidance](https://www.health.gov.au/resources/publications/enhealth-guidance-potential-health-effects-of-mould-in-the-environment) notes there is no safe exposure limit for mould — exposure should be minimised regardless of the species. See your GP if you develop persistent coughing, wheezing, or skin irritation.
Q: Can I paint over mould to cover it?
No. Paint will not kill mould, and the mould will grow through the new coat within weeks. Always remove mould completely, treat the surface, let it dry thoroughly, and fix the moisture source before repainting.
Q: Is it safe for children to be in the house during mould removal?
The [Victorian Department of Health recommends](https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/mould-and-your-health) that children should not be present during mould removal. Cleaning disturbs spores and releases them into the air. Keep children and pets in another part of the house, or out of the home entirely, until the area is clean and dry.
Related Reading
[A Comprehensive Guide to Mould Removal](/cleaning-101/bathroom/a-comprehensive-guide-to-mould-removal)
[Is Hard Water Affecting Your Home and Health?](/cleaning-101/bathroom/is-hard-water-affecting-your-home-health)
[8 Bathroom Cleaning Tips That Save You Time](/cleaning-101/bathroom/8-bathroom-cleaning-hacks-that-will-save-you-time-and-money)
[Green Cleaning 101: Natural Cleaning Solutions](/cleaning-101/sustainability/green-cleaning-101-how-to-make-use-natural-cleaning-solutions)
[Methods to Remove Soap Scum from Bathroom Surfaces](/cleaning-101/bathroom/methods-to-remove-soap-scum-from-different-bathroom-surfaces)
Sources & References
**CSIRO** — [Dealing with Mouldy Houses](https://www.csiro.au/en/news/all/articles/2020/august/dealing-with-mouldy-houses). Referenced for expert insights on moisture as the root cause of mould, ventilation guidance, and limitations of bleach and vinegar.
**NSW Health** — [Mould Factsheet](https://www.health.nsw.gov.au/environment/factsheets/Pages/mould.aspx). Referenced for recommended cleaning solutions, dilution ratios, and safety precautions.
**Better Health Channel, Victorian Department of Health** — [Mould and Your Health](https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/mould-and-your-health). Referenced for health risks, vulnerable populations, and mask recommendations.
**Lisa Coulburn and Wendy Miller**, Queensland University of Technology — [Indoor Mould and Health in Australian Housing](https://pmc.ncbi.nlm.nih.gov/articles/PMC8835129/). Cited for Australian mould prevalence data and childhood asthma attributable to indoor dampness.
**Rogawansamy et al.**, University of Adelaide — [Antifungal Activity of Household Products](https://pmc.ncbi.nlm.nih.gov/articles/PMC4483703/). Referenced for vinegar's effectiveness against different mould species.
**Asthma Australia** — [Flooding and Mould](https://asthma.org.au/triggers/flooding-and-mould/). Referenced for safety guidance for people with asthma.
**US Environmental Protection Agency** — [Mold Cleanup in Your Home](https://www.epa.gov/mold). Referenced for professional threshold recommendation and position on bleach use.
**enHealth, Australian Government** — [Potential Health Effects of Mould](https://www.health.gov.au/resources/publications/enhealth-guidance-potential-health-effects-of-mould-in-the-environment). Referenced for national guidance on mould exposure limits.
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