Tanking slurry

[Deleted member 319273]

Hi, I have a wall with a chimney breast on the outside I’ve closed the fire opening and vented the chimney top and bottom, I plastered the fire opening and decorated after a few months damp patches started to show, I have taken the wall back to brick repointed all the gaps and put two coats of tanking on it, after a couple of days some damp patches have shown through the tanking is this normal

 

[freddiemercurystwin]

Tanking slurrys, assuming they're meticulously applied as per their instructions, still only work if the water pressure is less than they can cope with, it's extremely difficult to know if such a solution will be successful or not. Really, the source of the water ingress should be stopped.

 

[Deleted member 319273]

Thanks for your reply, the water originally came in through the flashing where the roof meet the chimney how long for I don’t know. I have had the chimney took down and a new roof put on so I would say the cause has been stoped,

 

[freddiemercurystwin]

Then the wall must still contain moisture.

 

[Deleted member 319273]

I must have this wrong, I thought you could tank a damp wall as long as you had stopped the source

 

[freddiemercurystwin]

But you're saying damp is still coming through? So the source cannot have been stopped yet. Or is it condensation?

 

[Deleted member 319273]

I’m in a bungalow I’m 16 brick down from the ceiling and the patches are in random places not all over, how can it be condensation, thank you for your comments im a bit stuck with this one