Has damp gone?

[bradsalmon]

Hi all,

I found a damp problem on the outer wall of my kitchen and thought I'd tracked the problem and solved it with some waterproof render.

After leaving for a couple of weeks to dry out, the stain and damp feel on the plaster disappeared so I thought it was safe to decorate. Proceeded to first paint a PVA/water mix over the plaster and then painted but a couple of small patches have flaked off. Nothing like the original size of the damp but still enough for the eye to see.

So do people think there's still a damp problem, just smaller maybe? Or is the plaster knackered and needs replacing? (isn't this something to do with the salts or something?)

Thanks,

Brad

[Andrew Gabriel]

Probably due to using PVA, which is not a good thing to use under paint as it stops it sticking. There are proper paint on stain blocks to use underneath paint.

[Stuart Noble]

Oil based undercoat should cure the problem if it's just salts residue

[meow2222]

seldom a good solution

not a good idea

is it falling off? is it exuding crusts of salt?

Bodge jobs like this often make things worse.

NT

[mail]

Dear Brad If the wall is wet from outside and is say 9" solid it will take the best part of a year to dry out not two weeks PVA is re-emulsifiable and blockers would be best to paint on once the wall had dried and you know it is not gone hygrosopic on you I suggest scrape off what you have put on down to bare plaster and for a distance around that is damp using a damp meter wait till it dries (if you have to one coat of light emulsion) and check with regular montioring using a meter and mapping the damp drying with a measured location recording When dry decorate if it varies with the RH it is hygoscopic and you will need to get shot of it It is likely this will have happened with gypsum plaster but if it is lime you have a better chance of it drying out

Chris

[meow2222]

heck of a lot quicker to paint it with distemper now and forget it. Distemper wont stop it drying.

NT