Flaking old emulsion paint - skim coat?

Hi friends, In my old stone-built house, I have stripped the woodchip wallpaper off the large wall in the stairwell, and underneath, I find that it was painted wi th cheap emulsion, much of which is flaking off. I also had to remove a lar ge patch of the old plaster+rendering where it was becoming detatched from the underlying stonework (it's a solid stone wall, circa 1850). I've patche d that with mortar, not quite flush, as I was intending to patch-plaster to finish off. There are also some other areas where the plaster was coming a way from the underlying rendering.

Considering of all the above, I'm thinking of skimming the entire wall, bec ause it might end up being quicker than fixing all the above issues. I have scraped off all of the easily-removable flaking emulsion. The remaining 75 % of the wall's emulsion seems sound.

I want to end up with an emulsioned wall rather than wallpaper, because, be ing a very old house, there is a very slight dampness in the wall. (I mean minimal.) I've found that wallpaper does seem to accumulate damp that it dr aws out of the wall, and then the paper become soft and discolouration can occur. I've found that by emulsion-painting such walls, I've had no such pr oblems, because I think the slight dampness can evaporate more easily, and there is no wallpaper to come unstuck.

My question is: Is it okay to skim over the old emulsion paint? Will it sti ck okay? I have some 'Thistle bonding coat' from B&Q. Is that suitable?

Should I spray the entire wall with diluted PVA prior to skimming, or will that inhibit the breathability of the wall?

Many thanks,

Al

Reply to
wasaol
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If you wire brush (lightly) off any flaky paint, PVA is the usual method to ensure new plaster sticks and stays stuck.

I am not sure how permeable it is - probably is to some degree, but how much?

Reply to
Tim Watts

If there is any question of damp then gypsum plaster will never be a long-term solution. Surely this sort of older property needs sand-cement base coat with lime-based plaster on top so that any moisture coming through or up the wall can wick away ?.

The paint that you have found might be oil-based and deliberately used to deter penetrating damp. Paying a decent surveyor for advice on damp treatment could pay dividends.

Maybe hack all the old plaster off and fix the damp before doing anything. Best of all, dry line internally with extra insulation?.

Reply to
Andrew

Thanks; The wall really isn't very damp, and definitely not to the extent t hat I want to spend time and money on trying to eradicate it 100%. I just w ant to get the wall finished and smooth-looking. The paint on the wall is r egular emulsion - not oil based.

Al

Reply to
wasaol

Thanks. The plaster underneath the emulsion is very permeable; it's light grey standard plaster and very absorbent. The emulsion paint is just regular (25-year-old) cheap emulsion, and not very permeable.

Reply to
wasaol

that I want to spend time and money on trying to eradicate it 100%. I just want to get the wall finished and smooth-looking. The paint on the wall is regular emulsion - not oil based.

The usual recommended thing for stone walls is lime. PVA reduces breathabil ity. Cement mortar eventually pulls the face off the stone when it fails. S PAB have leaflets explaining this stuff.

NT

Reply to
tabbypurr

Does rather depend on the stone. Sandstone, yes; granite, not so much!

Reply to
Martin Bonner

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