How do you deal with mould behind a wardrobe?

Mould behind a wardrobe in Singapore: why it grows

A wardrobe pushed close to a wall stops air moving behind it. Damp air then sits in the narrow space between the wardrobe and the wall, with nothing to carry it away. If that wall is an outside wall, or the wall of a room you keep air-conditioned, it can stay cool enough for moisture to settle on it. That moisture is where mould takes hold.

The same trapped air reaches the wardrobe itself, so mould on wardrobe back panels is common too. The back panel is often thin board, it sits right in the damp space, and you rarely see it until you move the wardrobe out.

The National Environment Agency (NEA) makes the airflow point in its energy-efficient interior design tips: "Avoid obstructing windows and pathways with large furniture pieces as they block airflow for natural ventilation." That tip is about windows and pathways, but the reason it gives, that large furniture blocks airflow, is also why the wall behind a wardrobe stays damp.

For wider questions about causes and cleaning, see mould questions answered.

Rule out a leak first

Before you clean anything, check whether water is getting into the wall. HDB's guide to ceiling leaks notes that untreated ceiling leaks may also damage electrical items and cause mould growth. Water seeping into a wall can feed mould behind a wardrobe just as easily, and no amount of wiping fixes that.

Signs that point to a leak rather than poor airflow:

• a damp patch that spreads
• a tide mark on the paint
• paint that is flaking off
• a bathroom or a water pipe on the other side of the wall

Mould from a leak returns however often you clean, so the leak comes first. If you see any of these signs, have the source found and fixed, then let the wall dry out before you deal with the mould. The guide to water seepage through a wall has more on finding where the water comes from.

Cleaning the wall and the back panel

Empty the wardrobe and move it away from the wall so you can reach both surfaces. Wipe the mould off the wall and off the back of the wardrobe, then let both dry fully before you put anything back. The guide to mould on the ceiling sets out the cleaning method, and you can follow it on a wall.

NEA's cleaning guidelines for residences recommend that the home is ventilated, especially during and after cleaning. Open the windows while you work, and keep them open while the wall and the panel dry. A fan pointed at the wall helps it dry faster.

Check the back panel closely once it is dry. A panel that has swollen, gone soft or stained right through may need replacing rather than another clean. A handyman or the wardrobe's maker can tell you whether the panel can be swapped on its own.

Stop it coming back

Once the wall is clean and dry, the aim is to keep air moving behind the wardrobe. NEA's guidance on improving ventilation and indoor air quality says: "Occupants of residential homes may improve home ventilation by opening doors and windows. Fans can be used to promote air circulation when needed." HDB's wall care tips include facilitating cross-ventilation in the flat and re-painting the walls regularly.

A few simple habits help prevent mould in wardrobes and behind them:

• Leave a gap between the wardrobe and the wall when you push it back, so air can pass behind it.
• Keep damp clothes and towels out of the wardrobe until they are fully dry.
• Look behind the wardrobe now and then, so you spot new marks early.

Musty clothes and when to get help

A musty smell often comes before you can see any mould. If clothes in the wardrobe smell stale, wash or air them, and make sure they are fully dry before they go back. If a wardrobe mould smell lingers after cleaning, leave the doors open for a while and keep the room aired.

Cleaning one patch yourself is often enough. If the mould keeps coming back after you have cleaned and aired the room, or it covers a large area of the wall, the next step is a leak check if you have not had one, or a deep cleaning of the room. Price depends on the job, so compare a few companies before you book.

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