Paint flaking off internal walls

[RrogerD]

The matt emulsion white paint is flaking off of a couple of my internal walls. At least I think it's the paint itself and not efflorescence as I've read elsewhere on here. Any ideas how to remedy it?

I do have a long-standing water-ingress / damp issue in these walls and yes, I know that I should get this resolved first but, it is a major headache and I've absolutely no idea what is causing it. The flaking paint is the biggest concern at the moment.

I'm planning on: scraping back the loose stuff; applying SBR and then a vinyl matt. I assume that this will keep things at bay?

 

[Wayners]

I wouldn't use anything like SBR as you could be trapped moisture in...
What you can do.
Buy a couple of indoor humidity sensors that are under £10. See what that tells you as it could be condensation.

Find out if you have lime plaster, and if you do don't use anything gypsum based

Do you have a damp course in walls? You can fit dry rods yourself to fix.

You can watch skillbuilder on YouTube regarding humidity and condensation.

 

[RrogerD]

I wouldn't use anything like SBR as you could be trapped moisture in...
What you can do.
Buy a couple of indoor humidity sensors that are under £10. See what that tells you as it could be condensation.

Find out if you have lime plaster, and if you do don't use anything gypsum based

Do you have a damp course in walls? You can fit dry rods yourself to fix.

You can watch skillbuilder on YouTube regarding humidity and condensation.

Hi. Thank you for your reply.
Interesting re not applying SBR. I had assumed it was external, coming in but now I'm not too sure. I did purchase a humidifier for the property (it is tenanted) and asked that they use it religiously. I'm not sure how much they did do so over the cooler, wetter months, when they stopped using it and, when the paint flaking issue started. Whether the two are connected or not.
The attached pics were taken back in Dec last year when I scraped off all of the loose stuff and then re-painted with Wickes cheapo trade matt emulsion. Perhaps this is part of the problem?
The odd thing and as I say, part of the bigger problem, is that this damp is all around this one external corner at ceiling height downwards. There is no obvious signs of damp in the walls in the bathroom above nor, in the render to the outside. Yes, it could be a leak in the bathroom above but, I have in the past had the boards up and nothing obvious. Plus, the problem seems to have gone away with the drier weather, suggesting rain ingress rather than an internal leak. Or, condensation of course (?)

 

[Wayners]

Just the outside wall has the problem?

 

[RrogerD]

I've just heard back from the tenants.

Just the outside wall has the problem?

Yep. Two outside walls.The window wall and the back one in the middle pic.

 

[RrogerD]

I've just heard back from the tenants. They say that they used the dehumidifier until April, for about 4hrs each day and collected a 'container' full each day. Whether this is a reflection on the amount of condensation being produced or, it's extracting the dampness from the wall, I don't know.

 

[Wayners]

Probably pay you to get it looked at.
Camera in the cavity ect