Help! I've got damp!!!

[thecakefairy]

Hi all,
Moved into a beautiful flat in June.
It's immaculately decorated with no sign of any mould on walls, not even in the bathroom.
Windows open when possible.
Some drying of washing indoors as when absolutely necessary.
I have found some belongings have gone mouldy in the bedrooms.
A fold out foam chair, a few clothes and the side of my dressing table chair. All cleaned off easily and dried.
The two bedrooms particularly feel wet in the air.
The place was left empty the whole of last winter. I presume with no heating on.
The radiators are massive and super modern and so is the boiler and I've put the heating on a few times but then get too hot almost straight away!
I'm just off to buy a digital hygrometer to measure the moisture in each room but thinking of buying a dehumidifier but then keep thinking after a winter of good heating and ventilation things might sort themselves out.
Any advice or ideas?

how old is it?

what floor is it on?

how long do you run the extractor fan during and after every shower or bath?

how long do you open the windows each day?

when you drape wet washing inside your home, how do you remove the water?

Hello,

It's ground floor and built in 1988.
No extractor fan in bathroom but I open the window for at least an hour and then leave it a fraction open all day.
If I do put washing indoors, I put it in the dining area next to open windows or patio door.
I've started to use the heating a bit and the flat warms up immediately but it's not really cold enough to justify it really.

1988 should be free of water leaks and damp. I expect it has draught-proof plastic windows. Check under radiators, bath and sink for any signs of water.

Most likely cause will be insufficient ventilation. A bathroom extractor is more dependable than a window, because the wind direction may not suck air out of a window. You will get better ventilation if you slightly open a window on each side of the flat, but as you are on ground floor you don't want to attract burglars. If your windows have trickle vents, open them and leave them open.

Wet washing is a terrible cause of damp, and some condenser driers emit varying amounts of steam. You will know if the windows steam up.

If you own the flat and are not too hard up, get an extractor fan fitted, wired to come on with the light switch. Better ones can be quieter and more powerful than you may have seen elsewhere. Have a kitchen extractor done at the same time. Recirculating hoods have no effect on steam.