How do you remove bathroom mould?

Safe products and ventilation

NEA's guidelines for cleaning and disinfecting homes say to prepare and apply disinfectants according to the manufacturer's guidelines, allow the stated contact time and use the protective equipment the product's Safety Data Sheet prescribes. NEA notes that household bleach (sodium hypochlorite) is the most widely used disinfectant and lists hypochlorites as fungicidal. Dilute bleach only as its label directs, and follow a mould remover's own instructions rather than a mix you read about elsewhere.

NEA also recommends ventilating your home, especially during and after cleaning and disinfection, to reduce the concentration of disinfection products in the air. Open the bathroom window and door before you start, and run a fan if you have one.

How to remove mould in the bathroom: tiles and grout

Use these steps for mould on wall and floor tiles and for black mould on grout. NEA advises cleaning bathrooms from high to low (wall to floor) and from cleaner to dirtier areas, such as the shower before the toilet bowl.

1. Ventilate the room. Open the window and door, and switch on a fan if you have one.
2. Protect your hands and eyes. Wear gloves, plus eye protection if the label or Safety Data Sheet calls for it.
3. Scrub off loose mould. Use a stiff brush with detergent and water on tiles and grout lines, rinsing the brush often.
4. Apply the mould remover. Use a mould remover or diluted household bleach exactly as the label directs, working from high to low.
5. Leave it for the contact time. Wait as long as the label states, and do not add another product while you wait.
6. Rinse and dry. Rinse with clean water, then wipe or squeegee the surface dry.

Grout or silicone: when cleaning is not enough

Look closely at the silicone sealant along the shower tray, bathtub and basin. Spots on the surface may clear with the steps above. If the mould is inside the silicone and still shows after cleaning, the sealant usually needs to be cut out and replaced. Grout that stays stained after a careful clean may need regrouting rather than stronger products.

Questions to ask a handyman:

• Does the silicone need replacing, or will another clean do?
• Would regrouting part of the wall or floor deal with the staining?

Preventing regrowth

Mould returns where surfaces stay damp, so dry the bathroom quickly after every shower. NEA's guidance on improving ventilation says people at home can improve ventilation by opening doors and windows, and use fans to promote air circulation when needed.

Habits that help:

• Squeegee or wipe wet tiles, screens and the floor after showering.
• For shower curtain mould, wash the curtain as its care label says and let it dry fully before rehanging it.
• Fix dripping taps and leaking pipes promptly.

Some mould comes from a leak rather than shower steam. HDB says untreated ceiling leaks may cause mould growth and that neighbours should address a leak promptly. If the patches are overhead, see our guide to mould on the ceiling, and for habits that help prevent leaks and chokes, read our article on bathroom maintenance.

When mould points to a leak

Mould that keeps returning on the ceiling under the upstairs bathroom, or on a wall next to a shower or toilet, can mean water is getting in. For walls beside wet areas, ask a plumber to check for a leak and compare leak repair services.

For ceilings in an HDB flat, HDB explains that ceiling leaks happen when water from the flat above seeps through the floor slab, usually from wear and tear of the waterproof membrane and screed. Flat owners are responsible for the upkeep of their own flats, including the floor and ceiling slabs. For a leak between two flats, HDB's process is:

1. Talk to your upstairs neighbour.
2. Agree on a time for a check.
3. Engage a contractor jointly.
4. Let the contractor confirm the source and recommend a repair method.
5. Split the cost.

HDB says you negotiate price and scope with the contractor yourself. Repair methods it describes include re-screeding, which it recommends, and localised repair at the floor waste grating. Clean off any remaining mould once the leak is fixed.

When to stop and call a professional

Get help when:

• The mould covers a large area, such as much of a wall or the ceiling.
• It returns soon after a careful clean.
• You see signs of a leak, such as damp patches or dripping from above.
• Someone at home has breathing problems.

People with asthma or allergies may be more sensitive to mould. If you have health concerns, see a doctor.

For widespread mould, book a professional deep cleaning and ask whether mould treatment on tiles, grout and ceilings is included. If a leak is the cause, arrange a leak check first, or the mould may come back. Cost depends on the job, so look at home cleaning prices and ask what each quote covers.

Questions