How to Remove Mould From a Bathroom

Sydney's humid summers and damp winters give mould plenty of chances to settle into bathrooms. It shows up as black spots in grout, a grey shadow along the silicone, or a speckled patch on the ceiling above the shower. Knowing how to remove mould from a bathroom properly matters, because wiping off the visible part without dealing with moisture means it will be back in a few weeks. This guide covers the safe way to clean mould from the usual bathroom surfaces, which products to use, when to call in help and how to stop it returning.

Why Mould Grows in Bathrooms

Mould needs three things: moisture, something to feed on (soap scum, skin cells and dust are plenty) and time. Bathrooms supply all three. Hot showers fill the room with steam, the steam condenses on cool surfaces like the ceiling and tiles, and if the room doesn't dry out quickly, mould spores that are always present in the air start to grow. The usual causes are: • No exhaust fan, a fan that's too weak, or a fan that isn't switched on. • Windows kept closed in winter. • Wet towels and bath mats left in the room. • Cracked grout or perished silicone that lets water sit behind the surface. • A hidden leak from a pipe, the shower base or the waterproofing. The last two are worth taking seriously. If mould keeps returning in the same spot no matter how often you clean, the problem may be behind the tiles rather than on them.

Safety First

NSW Health advises that mould can affect health, particularly for people with asthma, allergies or weakened immune systems. If anyone in the home has these conditions, they shouldn't do the cleaning, and you should speak to your GP if you're concerned about symptoms. When you clean mould: • Open windows and turn on the exhaust fan. • Wear rubber gloves, eye protection and a mask (a P2 mask is a sensible choice for mould work). • Don't dry-brush or dry-wipe mould, because it spreads spores into the air. Dampen the surface first. • Never mix cleaning products. In particular, never mix bleach with vinegar, ammonia or other acidic cleaners, because this can release toxic gas. • Follow the label on every product, and do a small patch test on painted or delicate surfaces.

What to Use

There's a lot of conflicting advice online. Here is a practical summary.

White vinegar

Undiluted white vinegar is a common choice for mould on non-porous surfaces such as tiles and glass. Spray it on, leave it for about an hour, then scrub and rinse. It has a strong smell that fades as it dries.

Commercial mould removers

Products sold specifically as mould removers, many of them chlorine-based, are effective at removing the staining that mould leaves behind, especially in grout and silicone. Use them in a well-ventilated room and keep them away from coloured fabrics.

Detergent and water

For a light film of mould on painted ceilings or walls, warm water with a little detergent and a damp microfibre cloth is often enough. Change the cloth frequently.

What doesn't work well

Bleach on porous material such as plasterboard, wood or fabric may remove the colour without removing the growth underneath. Mould that has grown through soft materials like that often needs the material replaced rather than cleaned.

Step-by-Step: Removing Mould From Each Surface

Grout

1. Spray the grout with vinegar or a mould remover and leave it for the time on the label. 2. Scrub along the grout lines with a stiff grout brush or an old toothbrush. 3. Rinse with clean water and dry with a towel. 4. Repeat on stubborn spots. Dark stains deep in old grout sometimes won't lift completely. In that case, re-grouting is the long-term fix.

Silicone sealant

Mould often grows into silicone rather than sitting on top of it. 1. Apply a mould remover gel or spray and leave it as directed. Gels cling to vertical joints better than sprays. 2. Rinse and dry. 3. If black marks remain inside the silicone after a couple of treatments, the silicone needs to be cut out and replaced. If you rent, raise this with your agent rather than doing it yourself.

Ceilings

1. Protect your eyes, because drips from overhead are the main risk. 2. Lightly mist the area with your chosen cleaner, or use a damp cloth or a mop head kept just for this job. 3. Wipe gently. Don't scrub so hard that you damage the paint. 4. Let it dry completely with the fan on and the window open. If ceiling mould returns quickly, check whether the exhaust fan actually vents outside or into the roof space, and whether the room has enough airflow.

Shower screens and tiles

1. Spray with vinegar or a bathroom cleaner and leave it for a few minutes. 2. Scrub with a non-scratch pad. 3. Rinse and squeegee dry.

Shower curtains, bath mats and towels

Wash fabric shower curtains and bath mats in hot water according to the care label, and dry them fully in the sun if you can. Plastic curtains with heavy mould are often better replaced.

How to Stop Mould Coming Back

Removing mould is the easy part. Keeping it away is about moisture. • Run the exhaust fan during every shower and for a while afterwards. If your fan is on the light switch, leave the light on a little longer. • Open a window where you can, even a little, especially in winter. • Squeegee the shower screen and tiles after showering. It takes less than a minute and removes most of the water mould needs. • Hang towels outside the bathroom or on a heated rail to dry. • Clean weekly. Regular bathroom cleaning removes soap scum and body oils before mould can use them as food. • Fix leaks and cracked grout promptly. If you're renting, report them to your agent in writing. • Consider a dehumidifier in bathrooms without windows.

When to Get Professional Help

Call in help when: • Mould covers a large area or keeps returning in the same place. • You can smell mustiness but can't see the source. • There are signs of water damage, such as bubbling paint, soft plaster or loose tiles. • Someone in the household is vulnerable to the health effects of mould. A professional cleaner can deal with surface mould across a whole bathroom, but water damage and failed waterproofing need a plumber or builder. Our house cleaning service includes bathroom detailing, and a full house deep clean tackles mould-prone areas across the whole home. If mould is showing up around air vents as well, our guide to vent cleaning and indoor air quality is worth reading.

Frequently Asked Questions

Is vinegar or bleach better for bathroom mould?

Vinegar is good for mould on hard, non-porous surfaces and is milder to use. Chlorine-based mould removers are better at lifting dark staining from grout and silicone. Don't use the two together, and never mix them.

Why does mould keep coming back on my bathroom ceiling?

Usually because moisture isn't leaving the room. Check that the exhaust fan works, that it's powerful enough for the room, and that it vents outside. Leave it running after showers, and open a window when you can.

Can I remove mould from silicone?

Light surface mould can often be removed with a mould remover gel. If the black marks are inside the silicone, it needs replacing.

Who is responsible for mould in a rental property?

Responsibility depends on the cause. Mould from a leak or a building defect is generally the landlord's to fix, while mould from everyday condensation is something tenants are usually expected to manage with ventilation and cleaning. NSW Fair Trading publishes guidance for renters and landlords. If you're unsure, report it to your agent in writing.

Need a Hand?

If your bathroom needs more than a quick scrub, contact iCleanPro for a detailed bathroom or whole-home clean in South West Sydney. Related guide: How to Clean Grout and Tiles Without Damaging Them

How to Remove Mould From Your Bathroom (and Keep It Away)