Wallpapering onto plaster with paint patches.

[The Night Tripper]

Hi All I'm doing some wallpapering at the moment - just heavy textured lining paper onto old (sized) plaster. But there are patches of paint on some areas of the plaster. I'd hoped that the general grip would mean that I could ignore these, but (especially at the edges of the paper, of course) I'm getting some lifting, grr. I assume this means that the paint is oil-based.

What's the best approach here? I am resigned to using PVA border adhesive at some edges, but I wonder if there's something I can to to get better adhesion over the other patches of paint.

thanks J^n

[Micky Savage]

Hi, Use some pva on patches.

I did result.

Regards,

Micky Leeds Uk.

[stuart noble]

Paste sticks fine to oil paint. It'll probably flatten out when it's dry.

[The Night Tripper]

Hi Stuart

'Fraid not ;-(. That's basically why I took the chance in the first place. The patches are quite small - 1ft across or so - and quite thin, with the plaster grins through in a few places. It's as though someone was trying out a paint colour, or 'wiping off' a roller. But the paper definitely isn't sticking there, and pulling off as it dries.

J^n

[Phil L]

Paste should stick firmly to any kind of paint, oil based or not.

If you are having trouble with these patches, they will need 'roughing up' one way or another to increase adhesion.

You can either give each patch a light sanding, or mix a small solution of PVA 1:1 with water (you'll only need an eggcup full of each) and add a spoonful of cement and paint this over each patch, so that when it dries, the surface is rough.

[Dave]

Border and overlap adhesive?

Dave

[The Night Tripper]

Hi Phil

That's an interesting idea, thanks. I had originally given the patches a sand (by hand) without effect. I will try something like this and report back...

Cheers J^n

[Phil L]

If you've already tried it without success then it's grease that is your problem - is or was this part of a kitchen or somewhere where it could get greasy? - if the answer is yes then it'll need washing down with some turps or white spirit on a cloth and allowed to dry

[The Night Tripper]

Hi Phil

Nope, it's in a hall/stairway. I sized the walls previously as well, and the size at least covered the patches (didn't 'puddle' over them or anything). Your idea is worth a try though. Maybe it's some weird/unexpected type of paint? (although I doubt it...).

J^n

[Rod]

Did you size the painted areas?

Did you use old-fashioned animal size?

Are you using starch paste?

I know I have done just what you are doing - and had no problems. But it was a long time ago.

[stuart noble]

The usual problem with painted plaster is that the paste doesn't soak into the wall, so the paper stays bubbled up in those areas. What's inside the bubble is wet paste rather than air. In the case of vinyl, you often have to prick the bubble or it will take forever to dry.

[The Night Tripper]

Thanks for the various pointers chaps. Nothing really that i hadn't thought of already, but still interesting. Having done some more experimenting, I think my trouble mght be dues to a combination of a couple of things:

- following recommendations I read of the wiki, I have been leaving the paper to soak for longer than I have done previously - 10 minutes or a bit more. I think that maybe for this paper (thick and slightly textured lining paper) this has caused the paste to 'over-soak' into the paper, leaving too little on the surface.

- I think I may be a bit over-zealous with the use of the 'finishing brush' if that's what it's called. I've always found it worthwhile being quite agressive with this in the past. However I wonder if this has been causing the paste to squidge away from the 'slippy' non-permeable patch areas, leaving little paste underneath these spots.

So currently I'm soaking for a little less time and being gentler with the brush. This seems to be helping - and most of the paint patches are now covered anyway ;-/. I will probably have to use some border adhesive in some areas, but I knew this anyway.

Thought I'd pass on these observations anyway.

Cheers J^n