Mould around windows in Cyprus homes

Why windows are a mould hotspot in Cyprus

Black spots on the sealant, dark grime in the tracks, greenish staining on the plaster reveals around the frame — mould around windows is one of the most common problems we see in Cyprus homes. The reason is simple: windows are where warm, humid indoor air meets a cold surface and condenses. That condensation runs into the frame gaps and tracks, sits there, and mould follows within days.

It’s not a sign of a dirty home. It’s a sign that moisture has nowhere else to go.

How the condensation forms

Everyday life puts a lot of water into indoor air: showering, cooking, drying clothes, even breathing. In a sealed room that air holds the moisture until it hits the coldest available surface — which is almost always the glass or the aluminium frame. When warm moist air touches that cold surface, water droplets form. In winter, or on a coastal evening, this happens night after night. The water pools in the bottom track, seeps under the sealant, and soaks into the plaster reveal at the frame edge.

That damp track and damp reveal are exactly where mould colonises: a surface, steady moisture, and still air in the gaps.

Cyprus-specific patterns

The cause is the same everywhere, but the local conditions shape where and when it hits:

• Nicosia. Cold, damp winters with single-glazed or aluminium frames that stream with condensation each morning. North-facing windows with little direct sun are worst.
• Limassol and the coast. Year-round humidity means windows condense even outside winter. Sealed high-rise flats trap the moisture, and the frames rarely dry out fully.
• Newer builds. Double glazing and tight seals are great for drafts but trap indoor humidity, so the condensation simply moves to the next coldest surface — often the frame edge and reveal.

If you want to understand the cause at your specific address, an inspection in Limassol or inspection in Nicosia measures the humidity and confirms where the moisture is entering.

What you’ll see

The usual signs, in roughly the order they appear:

• Water droplets on the glass each morning, pooling in the bottom track.
• Black or dark-green spotting on the silicone sealant, especially along the bottom edge.
• A dark, slimy build-up in the window track that won’t wipe away cleanly.
• Staining or softening of the plaster reveal around the frame.
• A musty smell near the window, strongest when it’s been closed a while.

What to do about it

For most window mould the fix is a combination of drying the surface and treating the growth:

1. Reduce the condensation. Ventilate the room after showering or cooking, wipe the track dry each morning in winter, and keep a window slightly open where you can. If the room has an extractor fan, use it.
2. Treat the growth. On the sealant and frame, an anti-microbial spray and surface seal clears the active mould and stops spores resettling — a lighter-touch job than a full removal. This is typically a treatment rather than a remediation.
3. Replace perished sealant. If the silicone has gone soft, blackened through, or pulled away from the frame, it’s holding moisture and needs replacing after treatment — otherwise the mould returns in the same gap.
4. Watch the reveal. If the plaster around the frame is stained or soft, the moisture has soaked in deeper. That’s past a surface treatment and into removal territory.

For the typical case — surface growth on sealant and tracks — mould treatment in Limassol or mould treatment in Nicosia covers the anti-microbial treatment and the ventilation advice to stop it returning.

When it’s more than a window problem

If the mould has spread from the frame onto the surrounding wall, if the reveal plaster is soft, or if the same condensation is forming on the walls too, it’s a sign of wider humidity in the room rather than just a window issue. In that case treating the window alone won’t hold — the moisture will find the next cold surface. That’s the moment to book an inspection so the whole room’s moisture picture gets looked at, not just the frame.