Sealing old ceiling before papering.

I'm papering a previously painted ceiling.

Q1: What the best way to seal/prime this old surface?

It's a mixture of bare plaster and old mist coat, with powder filler and caulk in the numerous cracks.

I don't know whether or not it had been PVA'd prior to painting.
(Which as we all know is bad practice)

I'm using non woven Variovlies V200 lining paper, with Erfurt Wallrock power adhesive, and I'm pasting the ceiling not the paper. So NOT your usual Polycell, standard lining paper.

The lining paper will be painted over.

Q2: Do I even need to bother sealing it when using this adhesive?

I was thinking Beeline/Guardz over the lot, but I have no intention of doing this job again so... Q3: I'm not worried about ease of future removal, so do I need to spend the money when I can just paste straight on?

Cheers
Deluks



The details:

I'd sanded down the old emulsion with a pole, and filled any cracks with caulk, and had put the first roll of paper up, all was well.

When I put the second roll of paper up, I'd not quite got it into position, so had pulled it off slightly at one end to reposition it, and to my horror, big patches of the old paint came off, which were left stuck to the paper, and now meant I had bare patches of plaster that had no adhesive on them, and bits of old paint stuck to the back of the paper, which would surely show through when I repositioned the paper.

So I pulled the new paper off, and ended up removing the old paint layer with a snap-off knife (took a few hours!) the blade was able to slide between the emulsion layer and the what you see in the picture. The old paint came off in stiff flakes, sharp edged like a broken eggshell.

You could paste the ceiling to soften the old paint and then scrape the paint and paste off. Messy though.

Zinsser BIN is an option but not cheap. I haven't used Guardz though (it too is made by Zinsser). A cheaper but very smelly alternative would be to roll the ceiling with oil based primer or undercoat.

I'm not too fussed whether the white paint that's currently on is removed or not, it's very thin and well bonded, it survived my scraping process with an Olfa blade.
My only reservation with using any sort of paint over it would be a potential reaction with the Wallrock Adhesive, I think this might be what caused the old emulsion to come off in big flakes, as my prior scraping and sanding saw none of the old emulsion come off at all.

Your experience suggests that the old paint isn't "very well bonded". The water in the adhesive has caused it to delaminate from the plaster, hence my recommendation that you use BIN or OB paints. The water in the adhesive should not soften up new paints applied over the old ceiling emulsion.

Just to be clear, the old paint that came off with the new paper, has now been completely removed. The white patches you see are the old mist coat, which seems firmly attached, although I can't tell what type of paint it is. (Must be 30+ years old)

Here's a pic that shows the old emulsion prior to it being scraped off.

Zinsser Gardz all day long.

It's tempting to bite the bullet, it's also tempting to save the cash! Guardz is water based, so won't that have exactly the same effect on the paint as the wallpaper adhesive?

For now, I've fixed a small patch of paper over the ceiling, I'll let it dry overnight and pull it off, and see how well it's adhered.

The Gardz is a specialist product which once applied anything can go over it. Paint or paper. Lots of modern sealers are water based, even for water stains.

Cool, sounds good.

I've pulled the 'test paper' off after it had dried, the existing paint has remained intact, so that's all good.
However trying out the adhesive straight onto the paint caused the paint to become instantly gooey, so I'm guessing the paint is reacting to the paste when wet, but when it dries, it reverts to being dried paint, and the paste just becomes dried paste on top. Problematic.

I'll get the Zinsser.

If the paint is becoming really gooey (very quickly) you may have distemper (or some other lime based paint).

I would suggest using the Zinsser to reduce the risk of the water in the emulsion bleeding through the lining paper and reactivating the old paint, which at best, might cause paper joins to curl up.

Got a tin now, less than a a score at Selco's, cheaper than I was expecting.

Cheers all!