How to get rid of mould in humid weather

In the Caribbean, mould isn't a sign of a dirty house. It's a sign of a humid one. Outdoor humidity regularly sits well above 70%, and mould grows happily on almost any surface once the air stays damp. That's why it turns up on the bathroom ceiling, the back of a wardrobe, a leather bag you haven't used since Carnival, or the shoes at the bottom of the closet.

The good news: most household mould is a weekend job. Clean what you can see, deal with the damp that feeds it, and build a couple of small habits to keep it away.

Before you start

Protect yourself

• Rubber gloves, ideally long ones.
• A well-fitting N95 mask. Scrubbing releases spores into the air.
• Goggles if you're working overhead, like a ceiling.
• Fresh air. Open windows and run a fan pointing out of the room.

When to call a professional

• The patch is bigger than roughly 1 metre by 1 metre (about 10 square feet).
• It's inside your air-conditioning unit or ducts.
• It came from flood water or sewage.
• It keeps returning in the same spot, which usually means a hidden leak inside the wall or roof.
• Someone at home has asthma, allergies or a weakened immune system. Ask your doctor before doing the clean-up yourself.

Walls, ceilings, tiles and grout

Hard, non-porous surfaces like tile, glass, sealed counters and painted concrete are the easiest to rescue.

1. Scrub with detergent and warm water. Ordinary dish soap removes most surface mould. Use a stiff brush on grout and an old toothbrush on corners and sealant.
2. Treat stains if needed. For black marks that remain, use a ready-made mould cleaner, or diluted bleach of no more than 1 cup of bleach to 4 litres (1 gallon) of water. Leave it a few minutes, then rinse.
3. Dry it completely. Wipe down with a dry cloth and leave the fan on. Mould comes back fastest on surfaces left wet.

Painted walls: once clean and fully dry, an anti-mould paint or primer is worth it on walls that stay damp, such as bathrooms and north-facing rooms.

Plasterboard (drywall), ceiling tiles and insulation: these soak up moisture. If mould is growing into them rather than sitting on the surface, they usually need to be cut out and replaced.

Clothes, curtains and linens

1. Take them outside and brush off loose mould, away from open windows.
2. Wash at the hottest temperature the care label allows, with your usual detergent. For whites, add oxygen bleach.
3. Dry in full sun. Caribbean sunshine is one of the best mould treatments there is: heat plus UV. Make sure items are bone dry before they go back in the closet.
4. Repeat once if stains remain. Spots that survive two washes are usually permanent stains, not live mould.

Shoes, bags and belts

Leather is a favourite for mould because it's absorbent and usually stored in the dark.

1. Brush off spores outdoors with a soft brush.
2. Wipe with a cloth dampened with a mix of equal parts water and rubbing alcohol, or water and white vinegar. Test a hidden spot first.
3. Dry in a shaded, breezy spot. Direct sun can crack leather.
4. Once dry, apply leather conditioner, and stuff shoes and bags with paper so air can't stagnate inside.

Furniture, mattresses and sofas

• Sealed or varnished wood: wipe with soapy water or diluted vinegar, then dry well. Pull furniture a few centimetres away from walls so air can circulate behind it.
• Unfinished wood and wicker: scrub gently, then dry in the sun. If mould has gone deep into the grain, light sanding may be needed.
• Sofas and upholstery: vacuum with a brush attachment (empty it outdoors), then spot-clean with an upholstery cleaner and dry with a fan. Large patches inside the cushions need a professional.
• Mattresses: small surface spots can be cleaned and sun-dried. If it's spread inside the mattress, replacing it is the safer choice.

Find the damp that's feeding it

Cleaning without fixing the moisture is like mopping under a dripping tap. Check these usual suspects:

• Roof leaks and cracked flashing, especially after heavy rain
• Leaking pipes under sinks and behind toilets and washing machines
• AC units dripping, or condensate lines that are blocked
• Blocked gutters that spill water down the walls
• Bathrooms with no window or no working extractor fan
• Clothes dried indoors, or put away while still damp
• Closets and wardrobes packed tight against outside walls

Keep it away for good

Aim for indoor humidity under 60%

A cheap digital hygrometer tells you where you stand. To bring humidity down:

• Run the AC or a dehumidifier in rooms that stay damp. A dehumidifier in a closed bedroom or closet makes a big difference.
• Moisture absorber tubs (calcium chloride crystals) or silica gel packs work well in wardrobes, cupboards and storage boxes. Empty and replace them when full.
• Open up the house on dry, breezy mornings. Ventilation beats humidity.

Store things so air can move

• Don't pack closets tight. Leave space between hangers.
• Use breathable cotton bags, not plastic, for clothes and bags you're storing.
• Leave wardrobe doors open for an hour now and then.
• Keep storage boxes off the floor and away from outside walls.

A 10-minute weekly habit

• Wipe the shower walls and bathroom ceiling dry
• Run the bathroom fan or open the window for 20 minutes after showers
• Check under sinks and around the AC for drips
• Empty moisture absorbers that are full
• Sun your shoes and bags for an hour (in the shade for leather)

This guide is general household advice. For large outbreaks, flood damage or health concerns, speak to a qualified mould specialist or your doctor.