Condensation & mould

Black mould is almost always a condensation problem, not rising or penetrating damp. It appears when warm, moist air meets a cold surface and water settles, usually in poorly ventilated rooms. We find why the moisture is building up and fix the cause, so the mould doesn’t keep coming back.

This is often the cheapest damp problem to solve, because the answer is usually ventilation and heating rather than building work. It’s also the one most often misdiagnosed and over-treated.

Signs it’s condensation

Condensation and the mould that follows have a recognisable pattern:

• Black, speckled mould in corners, around windows and behind furniture
• Streaming or misted windows, especially in the morning
• A musty smell in bedrooms, bathrooms and north-facing rooms
• Damp that’s worse in winter and in rooms you heat intermittently

If the damp is a low tide mark or a rain-driven patch instead, you’re looking at rising or penetrating damp.

Why it happens

Everyday life puts a lot of moisture into the air: showers, cooking, drying clothes indoors, even breathing overnight. In a well-ventilated, evenly heated home that moisture clears. In a sealed-up or intermittently heated one it condenses on the coldest surfaces, and mould follows. Modern draught-proofing and new windows often make older Brighton homes worse, because they trap the moisture that used to escape.

How we fix it

We assess how moisture is being produced and where it’s settling, then recommend the right combination of:

• Improved ventilation, from simple extractor upgrades to a whole-house positive input system
• Treating and removing existing mould safely
• Practical changes to heating and airflow that actually fit how you live
• Insulation advice where cold spots are driving the problem

We won’t sell you damp-proofing you don’t need. If it’s condensation, we tell you, and we fix the condensation.

What it costs

Condensation and mould work typically runs £300 to £1,000, depending on the ventilation solution. See the cost guide for the full picture.

Common questions

Is black mould dangerous? It can affect breathing and allergies, so it’s worth dealing with rather than just wiping away. Removing it without fixing the cause means it returns.

Why does it keep coming back? Because the moisture source is still there. Repainting over mould without improving ventilation never lasts.

Seeing black mould around your windows? Book a free survey and we’ll find the cause.