How can I stop damp coming through wall?

[Gary111]

Hi, I have a patch of around 1x 2 feet of flakng paint at the side of an old disused chimney breast.

I am wondering what's the easiest way to patch it up?

I have some mapei shower paint on membrane, I wondered about hacking that part of plaster and painting the membrane on the bricks before re plastering?

Alternatively fixing a new piece of plasterboard over the whole side of the chimney?
I don't want any damp to soak through dot and dab fixing though.

Any ideas please?

 

[jj4091]

Fix the leak and let it dry out first of all

 

[Gary111]

No idea how to do that tbh, I've tried several times

 

[omph]

Whats on the other side of the chimney? Pics would be nice - Inside and from outside.

 

[foxhole]

Disused chimneys need ventilation , is it capped and ventilated .?

 

[Gary111]

Yes

 

[Murdochcat]

Yes

If that’s the case then you need to find out how the damp is entering

 

[Gary111]

I have tried several times over the years to work that out, as it's just a patch of around 2 feet wide by 1 foot down, 2/3 up the wall, short of dismantling that part of the fireplace I don't know what to do.

 

[Gary111]

When I last looked into it, it sounded like there's a possibility of old soot remnants in there that have salts that could be causing it?

Maybe I should remove a brick where the problem is and try to clean ?

 

[JohnD]

post some photos first

remove a bricj and look inside. there may be a heap of damp builders rubble. water may be soaking up from the hearth (hearths have no dpm)

removing a brick will also increase ventilation. Are both flues vented top AND bottom?

 

[Gary111]

Thanks, sorry does both flues refer to 2 fireplaces in a 2 storey house?
It's 3 storey so tbh I'm.not sure how the flues work.
I tried drilling into the 1st floor bricked up fireplace fireplace but didn't get any draw from air coming in.

 

[Gary111]

 

[Gary111]

There are other areas eg on the other side of the room where I also get bubbling paint, particularly on corners of walls which I assume is the metal angle in the plaster, no black mould on the paint though.

 

[JohnD]

Stand back and take a wider pic of the entire wall. Include something to show scale.

Is this on the ground floor?

There will be a flue for each fireplace in the stack (and each chimney pot)

 

[Gary111]

post some photos first

remove a bricj and look inside. there may be a heap of damp builders rubble. water may be soaking up from the hearth (hearths have no dpm)

removing a brick will also increase ventilation. Are both flues vented top AND bottom?

Sorry my phone died when I was there so couldn't take a picture but I removed a section of plasterboard.
There was one brick removed already but I can feel another brick behind that.

Is there some way of doing a dpc on the fireplace and possibly rest of the place eg with the rods?

Would I then just replace the bottom section of plasterboard and dot and dab it?

Thanks