Tanking slurry over a painted wall

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Jab331

New Member
I'm trying to tank an old brick shed/workshop ready to be sand and cement rendered and the walls are a mixture of brick and blockwork. They are all in a terrible state and previous occupiers have attempted painting sections of the walls in the past and my question is do i need to remove all of the paint before applying the tanking slurry? What would be the negative of applying the slurry over the paint?
 

Danny

Administrator
hmmmm so I assume it will be a single skin then?

There have been a few topics on this... I will see if I can find out some links for you :D
 

Jab331

New Member
I will have a look now but @zolco has experience with this and I think he suggests creating a ccavity and studding the walls
I don't think creating a cavity is an option as I would like to hang some things on the walls that will be quite heavy, don't think board would take it. As someone with little experience i just struggle to see what problem tanking over a painted wall will do? it will still seal the wall won't it?
 

Danny

Administrator
I don't think creating a cavity is an option as I would like to hang some things on the walls that will be quite heavy, don't think board would take it. As someone with little experience i just struggle to see what problem tanking over a painted wall will do? it will still seal the wall won't it?
the wall will still be cold and will condensate :D
 

Densel

Member
Single skin work is always a pain like danny said its prone to condensation. You can add air bricks and vents to help. But to answer your painted brick/blockwork issue you should really scabble them(needle gun). It a horrific tool to use but it will give you a proper key to render over. Failing that stainless steel mesh and then render(v.expensive tho)
 
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