Damp loft party wall (former chimney)

[Tennis court Kevin]

Hi,
We live in a semi detached house, our house has the chimney removed up in the loft. Our neighbours, who are council, have theirs still intact. We have a nasty damp patch appeared on our wall that adjoins the neighbours chimney, this is always there but gets darker and lighter in certain conditions. The council are saying it’s not their problem but we have no pipe work or a chimney on our side so the problem can only be theirs? Anyone have any ideas?

 

[JohnD]

might be a roof leak. Post photos please.

 

[Tennis court Kevin]

Had stack inspected but surveyor and cowels placed on chimney pots, so no leaks

 

[tel765]

As above, a pic would help.

Presuming that its not a bare brick wall then
When the loft chimney breast was removed maybe the backwall/party wall soot was not cleaned off but just gypsum plastered over?
The solution would be to hack off the existing damaged gypsum plaster, wire brush clean any soot, and render back up with a sand and lime mix.

 

[Tennis court Kevin]

 

[Tennis court Kevin]

Lived in property since 2005 when chimney already been removed, patch started showing in 2016

 

[tel765]

One way or another you will have to hack off the damaged area. So maybe start by doing that and exposing your background.
There could be issue on the neighbour's side but thats the land of PWA's I believe. How come the council got involved is curious. Typically, BCO's swerve PWA issues.

 

[JohnD]

so you still have chimneypots but no chimney beneath?

stand back and show us how it was removed please.

include something to show scale in any picture.

 

[Nige F]

How come the council got involved is curious. Typically, BCO's swerve PWA issues.

It's a council house next door ted.

 

[^woody^]

Barring any leak from the stack, these look like tar stains from the chimney flue.

The only way to stop them leaching through, is to remove the plaster and coat the wall with a suitable barrier liquid, then replaster.

This is being caused by the neighbours flue, and you could require the council as landlord to remedy the situation or compensate you for the damage and repair costs.