Painting over water-stained plasterwork (emulsion)

[zcacogp]

Chaps,

Quick one. We have had problems with a leaking roof, producing large brown stains on the ceiling of our second bedroom. The leaking roof has now been fixed, and everything is dry, but I fear that when we re-paint the ceiling the brown marks will come through the new paint.

Is there anything I can apply beforehand to prevent this from happening? I seem to recall a special type of paint that claims to prevent this; what is it, and does it work? Or should I just put a layer of dilute PVA on first and then paint over that?

Thanks, in advance, for any advice.


Oli.

[Spudler]

In spray form... http://www.icipaints.co.uk/products/info/polycell_...

[shirt]

dulux stain stop or similar is what i use. however, when i had the painters in [fnarrr] they just used undercoat meant for woodwork. in both cases, the damp hasn't shown through after 6mths.

[RedWhiteMonkey]

In my experience the spray stuff is useless as it doesn't put down a thick enough layer to prevent leaching. The paint on stuff is effective and works well, but be aware it is a thick stuff and getting a even coating can be a bit of a pain.

[shirt]

agree with the spray comment, but with a roller it's dead easy to get an even coat.

[Laurel Green]

If Dulux still manufacture it; oil based Wheathershield will do the same job as the Stain-block. Drys quick but, stinks a tad.

[MrV]

If you want to go the posh route Zinsser blocks out pretty much everything and anything


http://www.decoratingdirect.co.uk/viewprod/z/ZINBI... (so you know what you are looking for)

Or if you have any oil based undercoat floating around at home it will do as good a job for simple water stains.

[giw12]

Some oil-based white paint will do the job.

[zcacogp]

If I use oil-based white paint (wood paint, for instance) then won't I have difficulty getting the next layer of emulsion to stick on top of it?

Thanks for the suggestions.


Oli.

[Grandad Gaz]

zcacogp said:

If I use oil-based white paint (wood paint, for instance) then won't I have difficulty getting the next layer of emulsion to stick on top of it?


Oli.

Not if it's an undercoat.

[zcacogp]

Thanks ... looks like I'll be digging out my tin of white wood undercoat then!


Oli.

[Laurel Green]

Just a word of warning; I have known undercoat to hold back a stain, only to be pulled through the UC once the emulsion has been applied.

[furtive]

The ceiling in my kitchen was heavily stained from the previous owners cigarettes. My builders gave it a coat of gloss before emulsioning it and that has done the trick. The stain stop stuff was too thick for such a large area - it's like treacle

[giw12]

zcacogp said:

If I use oil-based white paint (wood paint, for instance) then won't I have difficulty getting the next layer of emulsion to stick on top of it?

Thanks for the suggestions.


Oli.

No..not at all. If you're concerned then give the oil paint a light sand with 120 to key it.

Trust me though.......