A lot of homeowners notice the same thing every winter.
The mould doesn’t appear in the middle of the wall first…
👉 it starts around the windows.
Usually in the corners, along the seals, or around the frame itself.
And naturally, the question becomes:
“Why is it always the windows?”
We see this all the time in homes across Manchester — especially during colder months when condensation levels rise indoors.
In most cases, it comes down to a combination of:
- Cold surfaces
- Trapped moisture
- Poor airflow
- High indoor humidity
🌡️ Windows Are Usually the Coldest Surface in the Room
Even modern double glazing is colder than insulated walls.
That means when warm moist air inside your home touches the colder window area:
👉 condensation forms first around the frames and glass.
This is why you often notice:
- Water droplets on windows
- Damp window seals
- Mould around corners of the frame
before anywhere else in the room.
🌫️ Condensation Creates the Perfect Conditions for Mould
Black mould thrives in areas that stay damp regularly.
Around windows, condensation often forms:
- Overnight
- During colder weather
- After cooking or showering
- In poorly ventilated bedrooms
If moisture sits there repeatedly:
👉 mould spores begin to grow.
🧱 Cold Bridging Makes Window Areas Worse
Many mould problems around windows are linked to thermal bridging.
This happens when part of the structure becomes colder than surrounding areas.
Around windows, this can occur due to:
- Metal components within the frame
- Poor insulation around reveals
- Older solid wall construction
- Gaps around installations
👉 These colder areas attract more condensation.
🛏️ Bedrooms Often Suffer the Most
We regularly see mould around bedroom windows because:
- Doors are shut overnight
- Windows stay closed
- Moisture builds up from breathing
- Airflow is limited
👉 The warm humid air settles on the coldest part of the room — usually the windows.
That’s why many homeowners wake up to:
- Wet windows
- Damp window sills
- Black mould spots around the frame
🌬️ Poor Airflow Around Windows Adds to the Problem
Heavy curtains, blinds, furniture, and restricted airflow can trap humid air around the window area.
This means condensation stays there for longer.
👉 The longer surfaces remain damp, the easier mould develops.
This is especially common behind blackout curtains during winter.
⚠️ Why Cleaning the Mould Doesn’t Solve It
Many people:
- Wipe the mould away
- Use anti-mould sprays
- Repaint the area
But then it comes back again.
That’s because:
👉 the moisture source hasn’t changed.
If condensation continues forming around the window, mould will continue returning.
🔍 How We Diagnose Window Mould Properly
At Weather Wise Solutions Limited, we assess:
- Humidity levels within the home
- Ventilation and airflow
- Surface temperatures around windows
- Thermal bridging risks
- Condensation patterns throughout the property
Because the key question is:
👉 Why is moisture continually forming around the window area?
🛠️ How It’s Fixed
Solutions depend on the property, but commonly include:
- Improving ventilation
- Reducing indoor humidity
- Improving airflow around windows
- Addressing insulation gaps where possible
- Managing condensation levels properly
👉 The aim is to stop the surfaces staying damp long enough for mould to grow.
👨🔧 Simple Things You Can Do
A few small changes can help immediately:
- Open windows briefly each day
- Use extractor fans consistently
- Leave gaps behind curtains where possible
- Wipe condensation away regularly
- Maintain steady background heating
👉 These all help reduce condensation around windows.
📞 Need Help in Manchester?
If black mould keeps appearing around your windows, it’s worth getting the cause assessed properly before it spreads further.
At Weather Wise Solutions Limited, we’re a family-run damp company specialising in:
- Mould and condensation control
- Ventilation solutions
- Damp proofing
- Timber treatment
We’re also proud members of the Damp Proofing Association and the Federation of Damp, with CPD-qualified specialists in dampness in buildings.
👉 Book your free quote here: https://weatherwiseuk.co.uk/pages/contact
👉 Contact us today: https://weatherwiseuk.co.uk/pages/contact