Mould around window

[Festipal]

Despite replacement double glazing there is still mould around the window in my DSis's bedroom.

It's on the underside of the recess and around the seal of the window. She's looking to sell when lockdown is over so doesn't want to spend too much solving the problem. Does anyone have any advice please? She's wiped it down with mould remover quite a few times but it comes back and never really goes away. She has trickle vents which she leaves open. Thanks for your help. Photos attached. They are at the bottom by the windowsill, at the top under the recess and by the seal of the window at the sides.

Does she drape wet washing inside the house?

How long are the windows opened each morning?

Thanks for those questions. She has radiators around the house that she uses once a week to dry washing on in winter but has a utility room so hangs up the clothes on airers in there for 3/4 of the year.

She opens them when she gets up in the morning whilst in the shower in her separate bathroom so they're probably open for 15 minutes or so most days when it's not raining.

The black spots are typical of condensation.

Assuming it is not a loft conversion or something with bad insulation, it will be caused by excess humidity in the air.

Water vapour is lighter than air (hence clouds) so it rises through the house.

If her kitchen or bathroom has an extractor fan that works, she could leave it running with the wet washing hung up in there. Much better would be a washing line outside or a tumble drier.

No it's not a loft conversion and she does use a tumble dryer and line dry when the weather is good. What about the glasses of water by her and her partner's beds? I've noticed they have pint glasses which has always struck me as odd!

leaving wet washing around the house is like chucking pints of water at the wall. The pints in the glasses won't be the issue.

I rented a flat once which had a mold problem in the bathroom, despite me always leaving the bathroom window open, the bathroom door open and windows throughout the house were always normally at least cracked. I had to use neat beach to remove it however some ended up embedded, got a chunk taken out of my deposit for it

does the bathroom have an effective extractor?

Those are beakers.

There is no extractor fan in the bathroom but apparently she leaves both windows open in there whilst showering and for an hour afterwards with the door closed. All showers have a 'door closed rule' (sensitive smoke alarm outside) and the mould is only in her bedroom which is diagonal from the bathroom. Not her DS's bedroom opposite.

She wants me to clarify she usually uses the tumble dryer except stuff that can't be tumble dried and that gets hung up on the airer in the utility room or if that's full on the radiators.

Its from drying washing on the radiators and shower steam .

Buy a bit of rope and some pegs

Running a dehumidifier might help.
We have had bad condensation. In our house the loft wasn't adequately ventilated. On cold nights condensation was forming on the underside of the roof, dripping down the roof and getting around the window frames. It stopped when we improved the ventilation in the loft space.
On a cold night go in the loft and touch the underside of the roof. If it is really damp it probably isn't adequately ventilated.

I'm not sure how a rope and pegs will solve the problem given it's literally impossible to dry clothes outside when it's raining?

She mainly uses the tumble dryer in winter when she can't use her airer in the utility room with an extractor fan. She has a rotary dryer in the garden for spring through to autumn when it's not raining. Her bathroom door is closed when everyone showers due to sensitive smoke alarm outside the room.

Good point about loft ventilation. Because it's only her bedroom it could be a spot in the loft. I'll suggest a trip up on a cold night.

She tried a dehumidifier but there was no noticeable difference after a year of using it.

All other suggestions welcome.

Although it very orobably is the drying of the washing have you checked outside the house. Our daughter had damp by her window and it was because the brickwork had gaps in it and needed pointing, took ages to come to that conclusion, get is mended then for it to dry out enough to be sure it had been the problem