Mould Stains on Lime Plaster Wall

[Flyfisher]

Having now fixed the damp problem that resulted in the mould in the first place, I'm thinking about decoration. I've thoroughly washed down the wall with a dilute bleach solution but it hasn't fully removed the mould stains.

Any suggestions for preparation before painting so that the stains don't show through the paint?

I'd prefer not to have to hang lining paper if possible, but am prepared to if it's the only solution. I'm planning to use F&B casein distemper but am not sure how well it will cover the staining so thought I'd ask if anyone has had a similar experience before just trying it anyway.

 

[andrew gayton]

try this.

using a razor blade held at 90o to the surface G E N T L Y scrape the surface to remove the staining. Don't gouge and use the whole length of the blade. Then use the distemper to prime the area.

 

[skier-hughes]

Our 3 coats of casein distemper gave a very good coverage, one section I painted for the tv so it looked finished and it covered the old paint etc and looked exactly the same, so much so, I haven't got round to doing anything about it yet!!

 

[Flyfisher]

I'll try the razor blade (Stanley knife blade?) idea on a small patch, though I don't fancy doing it for the entire wall!

If I can get the worst of it off then hopefully the paint will cover it. Again, I could try a small patch to test it.

I have the same problem to solve on a patch of ceiling where the roof used to leak. All dry now, and the plaster itself has survived surprisingly well, but plenty of mould stains to deal with.

 

[Keithj]

You may disapprove, but have you thought of Classidur? It solved some fire damage and water stain problems in a church near here. Cheap it isn't, but it seems to cover anything.