Wall plastered but stains showing through emulsion

[king.inter]

Hello all, I could do with a little help, heres the problem.

I removed a chiney breast from my house, ground floor, 1st floor - into the loft and is on an internal shared party wall. Ground & 1st floor was plastered about 2 months ago (by a tradseman) and while drying out, on the ground floor there were a few dark patches which kind of follow the line of where the removed chimney flue went. (Soot on the wall). The plasterer sealed this with what I presume was PVA before plastering. The problem I am having is that after emulsioning over this plaster, the dark spots keep showing through as yellowish stains (after 2 white dulux coats & 3 coats of Crown magnolia). I sealed the wall first with PVA before painting that was about 1 1/2 months ago & started painting it last night. The stains are abouthalf way up the wall to the ceiling. How can I stop these stains showing through?

Please help

 

[Zampa]

PVA wont seal stains like that..it will however draw them through to the surface.

Use dulux stain block, couple of coats then allow to dry and re emulsion.

If you cant get that try white knotting.

 

[king.inter]

Thank you for your advice, I will give it a go. Speak to you soon.

 

[king.inter]

Can I put stain block over the emulsion, or do I need to sand it back to the plaster?

 

[confidentincompetent]

Can I put stain block over the emulsion, or do I need to sand it back to the plaster?

Put the blocker strait on emulsion no problem. If you need to know about tar stains this might be helpfull.
http://www.decoratingdirect.co.uk/viewprod/z/ZINBIN/

good luck.

 

[acurachris]

Hi

You can also use gloss (white). The gloss is oil based and will stop the stain. Then emulsion over in your chosen colour once dry.

You probably already have the gloss, rather than buying stain blocker!

Good luck

 

[king.inter]

Started rollering on the stain blocker & it started to pull the emulsion off the wall where the stains are Anyway scraped the paint back to the plaster & gave it 3 coats of stain block & it seams to have covered. Will be emulsioning again in a couple of days, I'll let you know what happens

 

[confidentincompetent]

Hi

You can also use gloss (white). The gloss is oil based and will stop the stain. Then emulsion over in your chosen colour once dry.

You probably already have the gloss, rather than buying stain blocker!

Good luck

Problem is chris hes got soot stains and that will bleed through gloss, also putting gloss on he will then have to wait 24 hrs for it to dry. abrade to key, then two coats of emulsion on the gloss. I would'nt use gloss for stains anyhow, undercoat is better (on water stains).

Sounds like the emulsion was reacting underneath with the soot/tanning, if I had seen that I would have thinned blocker a bit more and rolled a slightly heavier coat on. Hindsights a good thing after the event

 

[king.inter]

The stained paint had to come off anyway, you could scrape it off with your fingernails & it was soft. Good news is though, after putting 3 coats of stain block on, it seams to have covered without any signs of the stains. Will be emulsioning later - fingers crossed it should be cured

Chris