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Damp/ tacky chimney wall

We stripped the chimney breast in the main bedroom and when we came to re decorate it a couple months later we noticed it felt tacky. There was no sign of damp when we stripped the wall.

We had a roofer round and he re pointed and set all the ridge tiles and fixed a few broken tiles. This was in early March.

The wall then dried out, and is now stained brown. We thought it was okay but when we have come to redecorate it this weekend it went tacky again, then Sunday and Monday it was dry again.

The chimney has been dropped so there is no stack and there is flue or fire down stairs.

We don't know if the roof is possibly leaking again or if there is another problem and we don't really know who to get round to look. Roofer or a different type of tradesman!!

Have we given it enough time to dry out?

2 Answers from MyBuilder Roofers

Best Answer

It sounds to me like you have salts in the plaster. Just as if you were to leave a pan full of water to dry out, then a white film will remain, the original water from the leak has dried out and deposited salt on the surface. These salts are hygroscopic, ie they absorb the moisture from the atmosphere leaving the wall damp which then dries depositing more salts and on and on. Solution is very simple, take sandpaper to wall to remove salts then apply either a stainblock, aluminium primer, or a oil based undercoat then decorate as usual. Hope this is helpful.


Answered 16th May 2017

When you stripped the wall was it re plastered or just painted onto? If the later, you may have paste residue left on even if you've sanded it. Sand it again and apply a coat or two of a product called zinsser gardz. Then apply your two coats of a durable matt emulsion in a trade paint like Armstead durable mat.
Any staining will need a stain block applying before your emulsion.


Answered 16th May 2017

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