Damp patches on Party wall.

[tvs85]

Hey,
Ive got some damp which I can't work out where its coming from...

The back story:
So the wall is a party wall 9inch solid brick. Its at the back of the house and the wall extends into the Garden to make the garden wall. I've quickly tried to draw it out, hopefully this makes sense.

My bad diagram...

Untitled-1.jpg (33.67 KiB) Viewed 691 times

On the floor above there is a chimney which does not come down into the kitchen. It's vented at the top and bottom, and I've stuck my hand in the vent at the bottom and it's bone dry.

Two weeks ago we noticed the dip on the party wall, so we re-capped the external 6-foot section of the garden wall, hacked off the plaster around the damp, and got my cousin (a plasterer) to put a sand and cement (with waterproof aditive). Tonight I had a another look and the damp has re-appeared about a foot above the the original damp.
I've just taken this pic now...

Damp above the newly patched area.

The wall has had a damp proof installed, again with a sand and cement (with waterproofer) up to the normal height. All of these issues are above the damp-proof.

Further along the wall (away from the garden) there are a few very small (the size of a 5p coin) damp patches, which show themselves as efflorescence through the paint. see this pic...

The Neighbours have got tiles all along this wall, so I can't see any sign of damp on their side...

Any help or thought would be much appreciated! I really can't work out where the damp is coming from!

Cheers,

Tom

[welsh brickie]

the external house wall has mortar on the wall ties causing bridging of the cavity and showing damp on the interior wall.
Use a borescope inspection camera to see into the cavity.

[tvs85]

The party wall is not a cavity its nine inch solid thick brickwork.

Cheers

Tom

[welsh brickie]

not the party wall, your house wall

[tvs85]

The wall between the two houses, where the red arrow is pointing? That's a 9incj solid brick. So Is the external wall.

[tvs85]

You mean the wall between the two houses, where the red arrow is pointing? That's solid brick, so is the external wall.
Thanks,
Tom

[welsh brickie]

then thats the problem the house wall is drawing moisture from the party wall.Remove the internal plaster back to the brickwork up to 1 metre away from the party wall and to a height of 1.5m.
Paint the brickwork with a buitumin paint and replaster with limelight.