Painting over damp wall.

[Agile]

A friend had as an old building used as an old peoples day centre.

It has a basement area which has been full of junk and the small vent to the outside has until recently been blocked. It still smells rather damp even though the vent was cleared last week.

This area was renovated about 18 years ago with new plaster. The walls are solid red brick and below ground level. As it was not ventilated the plaster now has a roughened surface as a result of the damp flaking.

Someone has advised that she should get some kind of paint to "keep the damp in". If that was good advice then what kind if paint is needed?

My advice is that it should just be wire brushed and painted with a thin breathable emulsion which will allow moisture to dry out. If thats good advice then whats the best kind of paint?

Tony

 

[misterhelpful]

I don't think keeping the damp in is the right way to go, so would suggest your idea of allowing the walls to breathe and dry out is a much better option.

In old lime mortar plastered buildings a lime wash paint is usually the best option.

Something along these lines might be more suitable for your friends situation, if it has gypsum plaster.
http://www.earthbornpaints.co.uk/masonry-exterior-paint.php

I have never used it, and generally avoid working with damp walls like the plague, so can't really say if it's any good!!

 

[DrEvil]

I had a similar problem before and the advice I had was be very careful of using kind of paints unless you are sure problem that caused it in the first place has gone away, it only tends to push the problems somewhere else!

To share my experiences, careful inspection of the main issue showed some lead lining which had failed, so that was replaced. I also pulled back the plaster to the brick (it was a sizable area that had been affected), and ran a dehumidifier in the room for a while to make sure, then had it replastered and then decorated.

Somewhere else also had water seeping in through a cracked concrete seal which left some small black markings on the wall. Again once the problem was solved, I took the wall back to plaster, let it dry out over summer and then stainblocked, papaered and painted it.