Mould Returning in Your Wardrobes After Painting? The Real Fix

You scrubbed the back panel, wiped it down with bleach, let it dry, and applied two coats of anti-mould paint. The wardrobe looked clean for a season. Then the autumn rain came, the heating went on, and the black spots reappeared in exactly the same places: the bottom corner, the shelf underside, the joint in the carcass timber. The paint was probably applied correctly. The problem sits somewhere else entirely.

Timber and chipboard are volumes, not surfaces

A plastered wall presents a reasonably dense barrier. The materials inside a fitted wardrobe do not: particle board, plywood and softwood carcassing are open, fibrous materials that absorb moisture from the air and release it again. When mould colonises this kind of support, it does not stop at the surface. Its mycelium — the living, thread-like network — pushes several millimetres into the panel, following the fibres and the gaps in the glue lines.

What you can see, the grey or black staining, is the fruiting body and the spores. Cleaning removes that. The mycelium stays inside the material, dormant, and it can wait for months until conditions suit it again.

What paint actually does here

Paint forms a film on the face of the panel. It hides the staining and delivers an immediate, reassuring result. It does not sterilise what lies beneath it. The fungicides in mould-resistant paints work within the paint film itself: they stop airborne spores colonising the coating. They do not travel three millimetres into chipboard to kill an established mycelium.

Two things then happen. The mycelium reactivates as soon as the moisture content of the board rises, and works its way through or lifts the film — usually at an edge, a screw, or a joint. And the coating, by reducing the permeability of the visible face, slows the panel’s ability to dry. Moisture arriving from behind or below becomes trapped inside the board. Growing conditions end up better than before you painted.

This is why a repainted wardrobe often fails faster, and more severely, than one left bare.

The order matters more than the products

In almost every case I inspect, the work was done back to front. Painting is the visible, satisfying step, so it comes first, in the hope that everything else will follow. Building physics requires the opposite. Paint is the last operation, and it only makes sense once three earlier stages have been dealt with.

1. Find the source of the water

Mould needs water. Without it, nothing grows, whatever the coating. So: where is the water coming from? The realistic options are few, and each leaves distinct traces. Cold-wall condensation: the wardrobe is fixed against an uninsulated external wall, staining concentrates on the back panel and in the corners, the problem is seasonal and worsens when the heating starts. Rising damp: moisture comes from below, the skirting and the first few centimetres of board are affected, present all year. Leak or water ingress: damage is localised, often near a pipe, a window reveal or a flat roof. Inadequate ventilation: humidity is high throughout the property, several rooms are affected, windows run with water in the morning.

These are measurable conditions, not matters of opinion. Moisture content of the board, air humidity in the void behind the carcass, surface temperature of the external wall — all can be read with instruments. Two causes frequently overlap.

2. Treat the timber, or replace it

Once the water source is dealt with, the contaminated support needs attention. If the board is still structurally sound, a penetrating fungicidal treatment applied to bare, dry timber to saturation can reach the mycelium. Strip back to the bare material, remove dust, and make sure it is dry — treating a damp support dilutes the product and stops it penetrating. If the board is swollen, delaminating or crumbling under thumb pressure, treatment is pointless. Degraded chipboard does not recover. Replace it, and use that opportunity to choose a material suited to the room.

3. Get air moving

A sealed, packed wardrobe pressed flat against a wall is a stagnant box. Pull the unit three to five centimetres off the wall, remove or perforate the solid back panel, fit high and low vents in the doors, swap solid shelves for slatted ones. Without air movement the timber never dries, and timber that never dries will be recolonised, treated or not.

4. Then paint

Dry, treated, ventilated: at that point paint earns its place. It protects the surface and makes cleaning easier, and it lasts. Applied first, it simply postpones the problem by a season or two.

Have it measured before you redecorate again

If this is your second or third repaint of the same wardrobes, another coat is not the answer. A site inspection identifies THE cause: humidity readings taken behind the carcass, surface temperature of external walls, moisture content through the thickness of the panels, checks for rising damp at the base of the partition. You receive a written report within 48 hours setting out the correct sequence — cause, then treatment, then finish — and what needs doing in what order. As an independent expert I sell no building work and have no connection to the contractors who carry it out; the report is the whole service. English spoken. Free quotation, covering departments 06, 83 and 13. ☎ 04 22 46 06 04

📅 Mis à jour le 28/09/2026 — Cassini Expertise, expert bâtiment indépendant (06·83·13·40).