Stains on plaster walls still

[yottie]

Following a chimney leakage am having problems getting rid of patchy stains on wall, have stripped the wall-paper and applied thinned down primer, along with some "stuff" from a squeezy tube before applying matching emulsion which is on adjoining paper. The stains are fainter but still there. Do I need to apply a lining paper and, if so, what sort. Am not used to papering and would prefer not to !

 

[misterhelpful]

Can you define:

"stuff"

You need to either use a stain blocking paint/spray or a coat of thinned oil based undercoat to stop water stains leaching through water based emulsions

 

[yottie]

"Stuff" was a sqeezy tube with a sponge at the end, I think it was made by Polycell ? I did try a coat of thinned down oil based paint as recommended by a previous poster too, but to no avail I'm afraid. I have now applied about 4 - 5 coats of emulsion over the stains with minor success. As this is a chimney breast I wonder if the stains are in the brickwork, the walls are 102 years old and I wonder if the roof leak brought them out or they could have been there under the emulsioned wall-paper for some time without showing. The wall-paper was just removed from this part of the wall as it had lost adhesion after the leak (now cured)

 

[sparkwright]

You could put 100 coats of emulsion over, and the stain would still bleed through.

Another oil-based product is worth a try, a stain block or similar.

 

[Robbie uk]

Emulsion is water based so will activate the stain each time. An oil based or maybe even a shellac based sealer will stop it. If your using oil based undercoat don't thin it too much or it will fail to seal the area.

 

[yottie]

Thanks, will coat again, do I need to remove the emulsion before-hand.