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Painting damp walls

Hi Everyone, I’ve a client that has had some water ingress around windows and a wall due to there being no lead flashing on that part of the roof !!! all these have been fixed. My problem is that they want me to decorate while the walls are still damp !! are there any paints I can use while the walls are still damp ? any ideas would be appreciated. Many Doug

Hey Doug. Are the damp walls new plaster or the original plaster that’s become saturated? I am presuming it’s old plaster from the way you put it so whatever you do on that might cause problems. It’s possible the plaster will suffer once it does dry out so what you do now might end up being temporary.

In an ideal world you wouldn’t paint on damp walls at all. Is there no possibility they can get heating fans on the walls and a dehumidifier for a couple of days before you start work?

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Hi Greenpainting, Thanks for the quick response, yes not ideal, I’ve got a week before I start, I’ll get in touch with them to get some heating on them many thanks Doug

have a read up on Zinsser WaterTite - it can be applied to damp walls , cellars etc

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Watertite might cause problems though Dave. It’s designed to hold back damp to stop it coming through to the top coats. I think in this case the damp needs to be able to escape so whatever coatings are used it needs to be breathable. Watertite over damp plaster might cause it to blow and come away from the walls after time.

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thanks for that - I must admit Ive only ever used it to prime walls with dried and crusty efflorescence not actual damp!

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Been away so you have probably finished by now but I would suggest Humi -Stop by Toupret -

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I am doing a job, the customer is skimming the walls, but there is damp which has risen half way onto two walls, and around window frame ,with the humi stop by touprett, it will mean painting the whole wall in them three areas, we have left it to dry,any recomened rollers,and other tips much appraited.

They do waterproof skim coats now which is the best bet for this type of thing. I have tried water seals in the past but it traps the water and the plaster rots and blows. If the damp is settling damp - eg from humid air, you can get away with it, but if it will build up I am not sure if it is a wise idea. I can only vouch for alkali resistant primer. It’s good if the first coat is highly thinned and you have dried out at least the surface of the skim so it forms a rock hard shell when the paint penetrates and dries. Followed by a full coat.

Contract matt is fairly water resistant in that it lets the water through without bubbling.

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On this job I am going to advice the customer they need to find where the problem is,and cure it when the plaster has skimmed the walls,we will use a sealer to cover where the damp was,at the moment its just drying out,will give area a wash ,with krudcutter before the plaster skims that area,think that sounds about right.