Repainting vinyl silk emulsion when defects in wall

[Clive]

Hi,

I'm not an expert on emulsion - but I think the walls in a bedroom are emulsioned with vinyl silk - there's a slightly shiny surface to the wall. Now centimetre wide "spots" of emulsion have come off and we can see the plaster underneath. In places it is single spots others it's more like a "rash". Now I can emulsion on top (any gotchas?) but I guess the "shadow" of the lost emulsion will still be visible. How can I "mask" or "fill" the spots before I put the final coat on? I was thinking maybe some white undercoat to build it up first? Is there an old-diyers knack to tackling this?

Also the old saw of "hairline" cracks. I'm a Tetrion fan - but it is too thick for these cracks and I'm not keen on racking out bigger cracks to give a surface for Tetrion to bond to. Has anyone used the "inverted V" approach where the opened crack is wider "into" the wall and still narrow on the surface? The idea being the filler won't fall out. Any success anyone with this? What kind of tool should I use for raking out?

Thanks

Clive

[A.Lee]

Why have blobs come off? Is it a reaction with new paint? Or is the plaster falling apart? I've done 2 ceilings recently where when coating with emulsion straight over the old paint, the new paint would bubble up. The only cure for this fault is to scrape back to the plaster and re-paint. If you try a little patch of paint, to see if it reacts, and it does, then it may be possible to paint it all over with an oil based undercoat, let that dry, then emulsion as normal.

Unless the plaster is flaky, then it is best to not scrape any more off, just get a tube of decorators caulk, and rub that in to any cracks. If they are tiny, then a thick coat of paint should cover them. Alan.

[Brian Reay]

The important question is why the existing paint has come off. My first assumption would be that it, or the paint under it, hadn't bonded to the plaster. We had a similar problem and took the walls back to the plaster. Then start over.

A big job but probably the result you will end up with.

Brian

[Clive]

There must be ten 1cm diameter patches and two areas of "rashes" about

5cm diameter. There is nothing I can see (such as damp) in these areas that would obviously have lead to the paint/emulsion peeling. For the (vast) bulk of the walls and ceiling, the vinyl(?) emulsion looks in good condition but is "grubby" and a change of colour is required by the "customer". The idea of underpainting the exposed plaster with undercoat was to try and "build up" the paint depth in the areas the plaster is exposed. I remember reading somewhere that one can undercoat glossed walls as a basis for subsequent emulsining rather than stripping back with chemical stripper to bare plaster.

Clive

[meow2222]

sounds like it

Many have tried, but theres no easy solution.

Forget raking out the cracks, I dont know why its so often recommended. Just wipe a little filler on with a finger, and wipe off. Done.

Likely due to not wetting the wall before the first coat. The porous wall then sucks much of the water & glue out of the paint, leaving it weakly bonded.

Yes. I'd just leave it and paint over it if it'll be accepted. It wont be perfect, but 1 or 2 layers of emulsion will leave little sign of their absence. If you need perfection you've got a lot of extra work ahead. You'd need to strip the lot, and plaster damage is pretty much inevitable, so you've then got to patch fill or skim. The other option is lining paper, but thats far from perfect either - hence the suggestion to forget it and just paint. With bulky paints its worth filling the dings, but emulsion has almost no depth to it, so I shouldnt worry about it. Once theyre the same colour you probably wont notice.

NT