Is this damp? Do I have a problem?

[davide2023]

Hi,
some of you have followed my previous threads on wallpaper removal and lime plaster.
Today, while scraping away some very old wallpaper, I have found a very dark plaster underneath.
I am not sure what exactly the problem is, but I am wondering if something needs to be rectified here...

Let me know what you think. I already had in the plan to call a roofer to check all the gutters, now I am thinking it's even more of a need.

Cheers,
D.

 

[erikwoolf]

Has the plaster blown out in the area?

 

[Lacan07]

Difficult to tell, could be an historic leak now fixed. I doubt its serious, might just need a bit of time to dry out. The obvious culprit would be blocked guttering above, wait for some rain and watch what happens.

 

[RBailey]

The obvious culprit would be blocked guttering above, wait for some rain and watch what happens.

That's what I was thinking as well. I also see there is cracked render / pebble dash (cement I suspect) below the gutter and above the vent, would be an easy root in for moisture.

 

[davide2023]

Has the plaster blown out in the area?

It doesn't sound more hollow than other areas of this room, to be honest.

 

[Stevers]

The crescent shape could indicate condensation that has caused black mould. It happens where warm moist air gets trapped in cold corners.

 

[edscull]

I would clean the black bit with mould cleaner. Then wipe it down with white vinegar the next day.
Then open up the vent cover and just see if there is mould inside there as well. If so clean it. Then leave all to.dry and wait until it rains. These things are.a waiting game in old houses. Good investigation can hopefully save you money in the future.

 

[CarolineTheChemist]

I recommend drawing round the mark in pencil and putting a date next to it. If you can leave it for a few rainy months you’ll soon see if it grows or if it’s historic.

 

[MatthewC]

Twelve years ago I had similar marks on the walls of both my back bedrooms, but the cause was quite obvious - there were several holes in the ceiling plaster and you could see daylight through three or four of the holes! So I would check the roof itself as well as the gutter. Quite possibly water is getting in at the top of the wall and cannot escape through the exterior cement render...