Cheap stain block paint or treatment

[cheb]

I've been asked to redecorate an old house, it's got plasterboard walls and ceilings that have generalised mould staining from condensation rather than water ingress. My plan was to use cheap gloss paint and then emulsion. The aim is not perfection but just to be usable and not look unsightly.

Is there an easier or cheaper way of doing this? I've read of adding pva to emulsion paint and using that but the amount of pva is never specified. 10:1 paint to pva? 1:1? Anyone have an opinion or preferable direct practical knowledge?

 

[Blobber]

I wouldn't use gloss, use an oil based undercoat or primer thats all we used to do, is the proper stain block stuff expensive these days?

 

[tom2207]

zinser .. the red one it dries fast and is slightly harder to work with
if you paint slowly try the water based blue one , although they do a spray tin now too.

 

[ajlelectronics]

zinser .. the red one it dries fast and is slightly harder to work with
if you paint slowly try the water based blue one , although they do a spray tin now too.

I was always under the impression that you should use an oil based paint as a primer first and then overcoat with your chosen emulsion?

 

[123hotchef]

the zinser gear is good I did the wifes whole flat in it walls, ceilings and the wood work.

 

[MetalMonkey]

There is no such thing as cheap stain block, it's all expensive! I've just done a wall half with zinser and half with polycell - both seemed to do the job, the polycell was an old tin, no idea if the formula has changed as that seems to be a popular thing to do now.

I've found it best to roller a whole wall/ceiling with stain block so you get an even texture, otherwise the stain block shows through. You could also try an obliterating emulsion, which has a higher opacity and should help, but won't cover stains on its own.

 

[Olderisbetter]

Zinsser is the best but not cheap, I use it as the cost of time is often an issue, remove as much of the mould as you can before you treat and paint, my mate does a lot of rentals on a budget so he uses oil based undercoat as a stain block, a lot of the time mould makes people think there is damp but it can be bad ventilation and lack of cleaning, I just did 2 days on this bathroom it was black over the window

 

[cheb]

Thanks for that, Zinsser sounds like the best bet.

 

[frank horton]

only ever used oil based undercoat.....never failed......even for dried heavy water staining....

 

[Mick Annick]

Recommended by a professional

 

[addjunkie]

I use undercoat….two coats

 

[brightspark]

great using zinser stain block works well but no ones mentioned wash the walls down first using mold inhibitor to kill the spores otherwise your flogging a dead horse

 

[Screwdriver]

Don't paint over it yet!

I have literally just cleaned a ceiling with deep stains just by misting a spray of diluted bleach. Only works on white but my god does it work.

Once the stain is either removed or faded, then consider a "stain block" to stop further stains developing after the bleach removes the opportunity for the existing stain to poke through the new paint.

Vitally important to use a fine mist and not let the bleach run. Mist it on, dab away any drips, let it dry. Repeat until done.