Mould is the most common housing problem we see on our building sites – and the most misunderstood. The good news: if you act early and tackle the cause, you get rid of it for good. The bad news: if you only paint over it, it is back within a few months. Here is what really helps.
Spotting mould early
Mould often announces itself before it becomes visible. Watch for these signs:
- A musty, earthy smell – especially in corners, behind furniture or in the bedroom
- Dark spots or patches – usually black, greenish or grey, often in room corners, on window reveals or behind wardrobes on external walls
- Peeling wallpaper or paint – a sign of moisture in the wall
- Misted-up windows – condensation in the morning shows the air is too humid
Why painting over it doesn't work
The most common mistake: a tub of anti-mould paint from the DIY store, painted over, job done. The problem is that mould is not surface dirt but a living organism with a network of roots in the substrate. A coat of paint on top hides it for a while but doesn't take away what it lives on. As long as the moisture is there, it keeps growing – and comes straight through the new coat. The order is everything: first establish the cause, then remove it, then restore.
The three steps to a lasting solution
1. Find the cause. Where does the moisture come from? A thermal bridge (a poorly insulated spot where condensation forms), inadequate ventilation, a hidden water leak or a building defect. Without that answer, any remedial work is money wasted.
2. Remove it properly. The growth is removed with suitable agents – with little dust, so that no spores get into the room air. Where it has gone deep, some plaster or plasterboard has to be replaced; with us, the plastering team takes care of that straight away.
3. Restore and prevent. Only now comes the mould-inhibiting remedial coat. Where the causes are structural, we advise on insulation (against thermal bridges) – that too from our own firm.
How to prevent it
- Ventilate properly: open the windows wide several times a day (fully open, 5–10 minutes) rather than leaving them tilted – this swaps the damp air without chilling the walls
- Remove moisture where it is produced: ventilate after showering and cooking, put lids on pans
- Move furniture away from external walls: a few centimetres of gap lets the air circulate
- Heating: cold walls encourage condensation – rooms kept at an even temperature are less susceptible
Report mould – free assessment More on mould removal
As at May 2026. This article is general guidance and does not replace a professional inspection on site. If the growth is extensive or a health concern, you should always call in a specialist firm.
Mould – what our customers ask us
Is mould in the home dangerous?
Mould spores can irritate the airways and make allergies or asthma worse – especially in children, older people and people with a weakened immune system. Small patches are usually harmless, but widespread or recurring infestation should be treated properly, because it also attacks the fabric of the building.
Can I simply paint over mould?
No. Anti-mould paint over active growth is only cosmetic: the fungus keeps growing under the new coat and comes back. The mould must first be removed and the cause (moisture) dealt with – only then does a remedial coat make sense.
Why does the mould keep coming back?
Because the cause was not dealt with. Mould needs moisture – from a thermal bridge, inadequate ventilation, a building defect or water damage. If you only remove the visible growth, you are treating the symptom. That is why we always first establish where the moisture comes from.
When should I call in a specialist firm?
For areas larger than about the palm of a hand, for recurring growth, for mould behind furniture or in the wall structure, and always after water damage. Send us a photo – we will give you a first assessment, free of charge.
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