Damp patch help!

[Beach1983]

Hi! Hoping someone has experienced similar on here and can maybe point me in the right direction of which trade I need? This weird damp/drippy patch has appeared in my daughter’s bedroom - it’s the wall in an external corner below the picture rail (no damp above the rail or on ceiling). We’ve checked in loft and no obvious leaks, gutters cleaned last year and all checked off a ladder.

what else could be causing this? We did have some condensation issues in this room and the ceiling was damp but this had been resolved but adding insulation above this room in the curved (1930’s) sections off the ceiling which had none before.

maybe expert @pigletjohn might be able to help?

thanks!

Take a wider pic, all the way floor to ceiling please.

What is on the other side of that wall? Take pics please. Inside and out, all the way up to the roof and showing all gutters, downpipes and overflows. Where is the nearest shower or bathroom?

Does anybody drape wet washing around the house or hung on radiators?

How steamy are the windows on cold mornings?

I had a patch of condensation in my bedroom. I found there was a hole through the mortar between the bricks on the outside wall. The cold air was getting in to the cavity wall and causing condensation on the inside wall. I filled in the hole from outside, and the problem went away.

That might be worth checking.

@PigletJohn thankyou! ! I will take photos tomorrow when it is light!

only shower/bathroom is opposite side of the house (usual 1930s semi layout) this is the box room at the front of the house and bathroom at the back.

windows are all very wet in the mornings but are old UPVC that all need replacing (can’t afford atm) due to renovating the house and that’s last on the list! We tumble dry washing to try and help the condensation!

@MintJulia I did think maybe it was an issue with the mortar! Will send my husband up the ladder to have a look 🤣

Do your windows have trickle vents?

That looks like condensation to me, as it’s in a waterfall pattern. You need to make sure windows are opened daily, heating is on in there. Also make sure no washing etc is in there, maybe some of those dehumidifier pot things that you can get cheaply.

Have you got a picture of the outside of the property to this wall?

Did it appear after a very cold night? We get that sometimes aftet very cold nights on one bedroom wall in our 1930s flat. We know it isn't from outside as it is an internal wall and we are floor 3 of a 4 floor building.

It is however a very cold wall as it backs on to a communal area by a sealed up lift shaft.

We manage it by leaving the window open a crack at night and running a dehumifier during the day and evening.