Damp problem

[JoMc30]

Hi there, wondering if someone could shed some light on this problem. I have a rising tide mark of damp on an internal party wall on the ground floor. I marked it with a pen a while back and it has risen a little past this mark now. When this problem first appeared, I asked the tennants of the house next door if I could look at their wall and that was damp too. They have since moved and the landlord has disappered off the face of the earth at the moment so I cannot ask to see their wall again. I know that years ago, this wall in my house had a chimney breast on it, which was removed and I have all the paperwork relating to this from when i bought my house. I have no problems with damp anywhere else in the house. I
My question is what sort of damp could this be? Is it rising damp or could it be the fact that there used to be a chimney there and something to do with the salts in the wall from when an open fire would have been in use. Whatever it is will no doubt be expensive hence why I havent yet done anything with it will need to save!

 

[User]

If you haven't resolved it by now here's my 2 cents

I had same problem my guess would be some old black carbon sooted bricks they soak in any moisture in the air like crazy

I never found out whether it was rising damp or not but I hacked off the plaster and rendered with sand cement 3/1 with waterproof double coat (no waste of money damp proofing) and never had any problems again

 

[noseall]

I never found out whether it was rising damp or not but I hacked off the plaster and rendered with sand cement 3/1 with waterproof double coat (no waste of money damp proofing) and never had any problems again

I have echoed your points, regards chimneys and hygroscopics, in several posts. SBR preparation combined with water proof render will be the right way to go in a lot of cases.

You would still be advised to eliminate other obvious causes first. A dynamic or shifting damp problem is not usally attributed to hygroscopics though?

 

[^woody^]

horizontal tide marks are not likely to be salt or soot related

Chimneys may not have a DPC, and infilling of heaths may have been done without a DPM. Generally a fire or draught would keep a fireplace dry

Also, you don't know what is going on with next door's chimney

Also check if the plaster is touching the floor, and if skirtings are soft. What about carpet or underlay staining - this may eliminate a floor issue