Stopping Mould Before It Starts: Furniture in Queensland Humidity

Care & Prevention · The Furniture Canvas

Mould on furniture here is a moisture problem long before it is a cleaning problem. Spores are already in the air of every Brisbane living room; what decides whether they take hold is how damp your furniture is and how still the air around it sits. Here is what our showroom team tells customers as the wet season builds.

Why it happens here

Mould needs three things at once: moisture, still air, and something organic to eat. Break any one and it stops. A South-East Queensland summer supplies the first two for months — humidity frequently sits above roughly 60% for days on end, and warm nights mean a cushion that took on moisture at 4pm is still holding it at 7am instead of drying overnight. Shut a house up from eight until six and nothing inside it ever gets a chance to dry.

The third thing is supplied by ordinary life: dust, skin cells and body oils in the weave, and the sugars in timber under the finish. That part you cannot remove. Moisture and airflow are the two you control, which is why prevention is not a matter of scrubbing harder.

The spots that fail first

Mould rarely spreads evenly. It starts in one badly ventilated pocket. If you check nowhere else this summer, check these.

• Against an external wall. Masonry on the weather side stays cooler than the room air, so a lounge pushed flat against it sits in a narrow, still, cool gap.
• Under a lounge on a slab. Concrete holds cool and holds moisture, and a low-set piece traps damp air that never turns over.
• Inside a storage bed base. A closed box of bedding, in a bedroom, for months — see below.
• Behind a bedhead. The same still gap, plus eight hours of breathing and perspiration a night.
• A closed-up house. A fortnight away with the windows locked, a household where nothing opens Monday to Friday, or the spare room kept shut to save on cooling.
• The chaise corner nobody uses. The seat you sit in daily gets moved and aired; the far end does not.

There is a tell before anything is visible: a faintly earthy note as you walk in, which fades as your nose adjusts. Trust it.

Air and moisture: the whole game

Everything that works is either moving air across a surface or putting less water into the room. In rough order of how much difference it makes:

• Leave a gap behind everything. Five centimetres is the minimum against an external wall and ten is better. It looks like nothing in the room and changes everything in that gap.
• Get furniture off the floor. Legs let air pass underneath; anything sitting flush to a slab needs pulling out for an hour once a month.
• Rotate and flip the cushions weekly. Swap them end for end, turn them over, and stand back cushions on edge now and then. It keeps the foam wearing evenly too.
• Open up after the rain, not during it. Opening mid-downpour invites saturated air in. Wait for the sky to clear, then open the house properly for an hour or two.
• Get a crossflow going. Two openings on opposite sides so air travels through rather than swirling in one corner — one window alone does very little, and internal doors left ajar cost nothing.
• Point a fan into the dead corner. A pedestal fan behind a lounge for an afternoon is the most useful thing you can do after a wet week.

A dehumidifier earns its place in rooms that cannot be ventilated — a downstairs rumpus, a slab-level bedroom. Aim for about 45% to 55% relative humidity, and buy a small hygrometer too — it tells you which room is actually the problem. Air conditioning removes moisture as it cools, but only while it runs.

The hidden cause: drying washing indoors

A single load of wet washing carries litres of water, and every drop has to go somewhere. On a clothes horse in the lounge room it goes into the air, then into the upholstery, the curtains and the rug. If you must dry indoors, use one room with the door shut and a window open or a fan running, vent the dryer outside, run the bathroom exhaust fan after every shower, and keep damp towels off dining chairs and bed ends.

It is worth thinking about before you buy: a lounge on visible legs with an open underside behaves far better here than a floor-hugging design, which is worth weighing up while browsing our fabric sofas and couches.

What fabric, timber and metal each need

Once the room is under control, the piece itself matters. The three materials in most homes fail in three different ways, and our furniture care range is organised around that difference.

Fabric: stop it drinking

Upholstery is the most vulnerable thing in the house, because the weave traps the moisture and the food together. Vacuum with the upholstery tool every fortnight, into the crevices and under the cushions, and deal with spills the same day.

A protector is the next layer. It makes the fibres less absorbent, so a spill beads on the surface long enough to blot away instead of soaking into the weave. The Guardsman Fabric Protector is the everyday indoor version, for lounges, dining chairs and bedheads.

For fabric that lives harder — alfresco settings, cushions on a covered patio, a piece in an open carport — the Guardsman Weather Defence Fabric Protector is the outdoor-grade member of the same family.

Reapply after any deep clean. If you have had a couch steam cleaned, the treatment goes back on once the upholstery is completely dry — a lounge still damp in the foam is a bigger risk than the stain you removed.

Timber: look after the finish

Timber takes on moisture when the air is wet and gives it back when the air dries. The finish is what slows that exchange, so maintaining the finish is the prevention job. Keep timber out of the cool gap against an external wall, never leave a damp cloth or wet glass on a surface, and clean and polish at the start and the end of the wet season — the Guardsman Wood Care Kit covers both steps.

Metal: the condensation carrier

Metal does not grow mould, but it feeds it. A cool metal leg or bed frame in warm, humid air beads with condensation exactly as a cold drink does, and that water drips into carpet, or into the timber and fabric it is bolted to. Wipe it dry when you find it beaded, keep feet off damp concrete, and treat exposed metalwork with the Guardsman Weather Defence Metal Protector.

Storage bed bases: the hidden trap

Gas-lift storage bases are genuinely useful in a smaller home. They also create a sealed box in the most humid room of the house, with a mattress as the lid and nothing inside ever moving — bedding goes in slightly damp from the linen cupboard, the base stays shut for four months, and the spare doona comes out in April smelling of a caravan.

• Air it when you change the sheets. Twenty minutes with the base open, once a fortnight, keeps the air inside turning over.
• Store only what is bone dry. Anything that goes in damp is still damp in February, and it takes its neighbours with it.
• Choose the packaging deliberately. Keep bedding breathable in cotton bags, or seal genuinely dry items properly. The failure case is loose bedding thrown in and forgotten.
• Lift the mattress a few times a year. Stand it on edge for an hour and vacuum the compartment while it is open.

Construction matters too. A slatted base moves air under the mattress in a way a solid panel cannot, and an open-framed timber bed on legs sits in moving air rather than trapping it — one of the first things we raise in our wooden bed frames range. Whichever base you choose, pull the bedhead a few centimetres off the wall.

A wet-season rhythm

Three short routines, tied to the calendar and the weather.

Going into the wet season

• Pull every large piece off the walls and check the gap behind it.
• Vacuum lounges thoroughly, under and behind the cushions.
• Clean and polish timber; top up fabric protection on anything cleaned since.
• Empty and air the storage bed base, then put back only what is dry.

After a storm or a wet week

• Wait for the outside air to dry, then open the house and get a crossflow going.
• Run fans into the corners behind lounges and bedheads.
• Rotate the cushions, and wipe condensation off metal legs and fittings.

Before you go away

• Leave internal and wardrobe doors open so air can still move between rooms.
• Pull furniture away from external walls before you go, not after you get back.
• Wash and dry anything damp — nothing wet should be left in a closed house.
• For a holiday home, ask someone to open it up for an hour every week or two.

Prevention FAQs

• What humidity level does mould need to grow on furniture?

  Mould starts finding surfaces hospitable once relative humidity sits above roughly 60% for a sustained period, which is common through a South-East Queensland summer. Keeping rooms between about 45% and 55% removes the conditions it needs. A small hygrometer is the easiest way to find out which rooms are actually the problem.

• There are already mould spots on my lounge. What should I do?

  Treat what is there first, then fix the conditions. Our separate guide to removing mould from fabric furniture covers the removal process step by step. Once the piece is clean and completely dry, come back to the airflow and moisture measures here, or it reappears in the same spot.

• How much of a gap should I leave behind and under furniture?

  Five centimetres is the minimum against an external wall, and ten is better. Underneath matters just as much: furniture on legs lets air pass below, while a piece sitting flush on a slab traps damp air. If something must sit flush, pull it out and let it breathe for an hour once a month.

• Does drying washing indoors really cause mould?

  It is one of the most common hidden causes. A load of wet washing carries litres of water that has to end up somewhere, and on a clothes horse in the lounge room it ends up in the air, the upholstery and the rug. If you cannot dry outside, use one room with the door shut and a window open or a fan running, and vent the dryer outside rather than into the laundry.

• How do I stop mould inside a storage bed base?

  Treat it as a sealed box that needs airing, not a cupboard. Leave the base open for twenty minutes whenever you change the sheets, store only bone-dry bedding, and stand the mattress on edge a few times a year so the compartment can breathe. A slatted base moves far more air than a solid panel.

• Do fabric protectors prevent mould?

  They are one layer of the answer, not the whole answer. A protector makes the fibres less absorbent, so spills and damp bead on the surface and can be blotted away instead of soaking into the weave. It does not replace airflow and humidity control, and it needs reapplying after any deep clean, once the upholstery is completely dry.

Written by the A2Z Furniture team — five South-East Queensland showrooms at Rocklea, Virginia, North Ipswich, Bundall and Beenleigh, family-owned and operated since 2013. Last updated September 2026.