Grenada's air is warm and humid for most of the year, and during the rainy season, roughly June to December, relative humidity can stay high for weeks at a time. Mould and mildew love these conditions. Leather shoes grow a green film in a closet, books smell musty, grey spots spread across a bathroom ceiling and a black bloom appears on the shaded side of the house.
Mould is not only unsightly. It damages clothes, furniture and finishes, and it can aggravate asthma and allergies. The good news is that most mould problems in Grenadian homes have a handful of clear causes. Fix those, and adjust a few habits, and even an old house can stay fresh through the wettest months.
Why houses go mouldy
Still air. Mould grows where moist air sits. Closed closets, cupboards against outside walls, rooms shut up while the owner is away and corners behind furniture are the usual hotspots.
Cool surfaces. Air-conditioned rooms can create cold surfaces where warm, humid air condenses, especially if the AC is switched off and doors opened to humid outside air. Walls next to AC units and ducts are common problem areas.
Water getting in. Roof leaks, failed window seals, cracks in block walls, leaking pipes inside walls and blocked gutters overflowing against the house all feed mould from outside.
Rising damp. Ground-floor walls without an effective damp-proof course can draw moisture up from the soil, leaving a tide mark of peeling paint and salt deposits.
Daily moisture. Cooking, showers and drying laundry indoors add a surprising amount of water to the air. In a closed house, it has nowhere to go.
Ventilation: the traditional answer
Older Grenadian houses were designed around the breeze. High ceilings, louvred windows, fretwork above doors and verandahs that shade walls all keep air moving and surfaces dry. Many modern houses, built tighter for air conditioning and security, lose some of that natural ventilation.
Where possible, encourage cross-ventilation by opening windows on opposite sides of the house so the trade winds can flow through. Ceiling fans help keep air moving even when the breeze drops. Louvre windows, still common in Grenada, allow airflow while keeping out rain, though they can be draughty during storms and less secure than other types.
In bathrooms and kitchens, extractor fans vented to the outside, rather than into the roof space, remove moisture at source. Leave the bathroom door open after showering and wipe down tiles. In closets, louvred or slatted doors let air circulate, and leaving a small gap between stored items and walls helps too.
When going away, ask a caretaker to open the house regularly, or leave some ventilation in a secure way. A house closed for weeks in the rainy season can come back to mould on every surface.
Air conditioning and dehumidifiers
Air conditioning removes moisture as it cools, which is why air-conditioned rooms often feel drier. But it works best when the room is closed and the unit is properly sized. An oversized unit cools the room quickly and switches off before removing much moisture, leaving air cool but damp. Many split units have a dry or dehumidify mode worth using on humid days.
Electric dehumidifiers are effective in closets, storerooms, libraries and bedrooms that are kept closed. They need emptying or a drain hose, and they add to the electricity bill, which matters given Grenada's relatively high power costs. Small moisture-absorbing products containing calcium chloride or silica gel help in wardrobes and cupboards, though they need replacing regularly.
If you switch the AC off for long periods, open the room to air rather than leaving it sealed, as a closed room without cooling or ventilation is ideal for mould.
Cleaning mould safely
For small areas of mould on hard surfaces, a household can usually handle the clean-up. For large areas, or mould inside walls and ceilings, call a builder to find and fix the source first.
- Find and fix the moisture source, whether a leak, condensation or poor ventilation. Cleaning without fixing the cause means the mould returns.
- Wear gloves, eye protection and ideally a mask, and ventilate the room. Mould spores spread when disturbed.
- For hard, non-porous surfaces such as tiles, glass and painted walls, scrub with a mould cleaner or a diluted bleach solution, following the label. Never mix bleach with other cleaners.
- For wood and other porous surfaces, use a cleaner suitable for the material; bleach does not penetrate wood well and can discolour it.
- Dry the area thoroughly afterwards, using fans or AC if necessary.
- Wash mouldy fabrics in hot water where the fabric allows and dry them in the sun, which helps kill mould and removes musty smells.
- Repaint cleaned walls, if needed, with a paint containing a mildewcide suitable for the area.
Common mistakes
Painting over mould. Fresh paint over live mould soon shows spots again. Clean, dry and treat first.
Sealing a house too tightly. Closing every window and door during a long absence traps humid air. Ventilation, controlled and secure, prevents more damage than it causes.
Ignoring the outside walls. Black staining on the shaded side of the house usually means algae and mould growing on damp render. Pressure cleaning and an exterior paint with mildew resistance help, but check gutters and drainage too.
Storing documents and photos in cardboard. Cardboard soaks up moisture and feeds mould. Use sealed plastic containers with moisture absorbers for important papers, photographs and keepsakes.
Overlooking rising damp. Peeling paint at the base of ground-floor walls is easy to blame on bad paint. If it keeps happening, ask a builder whether moisture is rising from the ground.
When damp points to a building defect
Some damp is a symptom of a building problem rather than of humidity alone, and no amount of ventilation will fix it. Patches that appear or grow after heavy rain usually mean water is getting in: a roof leak, a failed flashing around a chimney or water tank stand, a crack in a parapet wall, or a flat concrete roof whose waterproofing has worn out. Damp at the base of walls that worsens in the rainy season can mean poor drainage around the house, with water pooling against the foundations.
Damp that appears in the same place regardless of weather may point to a plumbing leak inside a wall or floor. A rising water bill, or a cistern level that falls faster than usage explains, supports that suspicion. A plumber can isolate sections of pipe to find the leak.
For houses built into a hillside, which describes many properties around St George's, Grand Anse and the south coast, the uphill wall is often partly below ground. Without proper waterproofing and drainage behind it, groundwater seeps through. Fixing that properly can mean excavating and tanking the wall, so get a builder's assessment before spending money on surface treatments.
Seasonal habits that help
In the drier months, roughly January to May, take the opportunity to air the whole house, sun mattresses and cushions, and empty and clean closets. This is also the best time for exterior painting, roof repairs and sealing cracks, since materials cure better in dry weather.
As the rainy season approaches, check gutters, downpipes and drains so water is carried away from the house, inspect window seals, and service AC units so they dehumidify efficiently. During long wet spells, keep fans running, use dehumidifiers in closed rooms and avoid drying laundry indoors where possible.
Stored clothes, shoes and bags do best in breathable fabric covers rather than plastic, with moisture absorbers in closets. Leather items benefit from occasional wiping and airing. These habits take little time and prevent the slow damage that humid months otherwise bring.
Frequently asked questions
Why does everything go mouldy in the rainy season?
Relative humidity stays high for long periods between June and December, and mould grows wherever moist air sits still. Closed closets, rooms shut up without ventilation and surfaces cooled by air conditioning are especially vulnerable. Airflow and lower indoor humidity prevent most problems.
Is a dehumidifier worth buying in Grenada?
For closed rooms, closets, storerooms and houses left empty for periods, a dehumidifier can make a real difference. Running costs matter because electricity is relatively expensive, so use it in specific rooms rather than trying to dry an open house.
Is black mould dangerous?
Any mould can trigger allergies and breathing problems, particularly for people with asthma or weakened immune systems. Small patches can be cleaned with care, but large or recurring growth should be dealt with promptly, along with its moisture source. Seek medical advice if symptoms persist.
How can clothes be protected from mildew?
Keep closets ventilated with slatted doors or regular airing, use moisture absorbers, avoid overpacking, store items clean and dry, and use breathable covers rather than plastic. Sunning clothes and shoes occasionally in the dry season also helps.
Does air conditioning cause mould?
Air conditioning itself reduces humidity, but problems arise when units are oversized, poorly maintained, switched off with rooms sealed, or create cold surfaces where condensation forms. Regular servicing and sensible use usually prevent mould.
