Advice on skimming over rough old plaster

Hello,
After a bit of practice and a few disasters I can get a nice finish with plasterboard and a skim, for my next project I need to skim over some old plaster. I've removed paper which has left a rough surface, some hollows of variable size, a few holes. There's also a chase which has been filled and stands a little proud. I've knocked off all the loose stuff and sealed with PVA.

My question is, what next? Should I go straight for finish on tacky pva and use a varying thickness with the first layer to smooth the problem areas? Or put a tight coat of bonding round the lot and skim onto that? If bonding, how long should I wait before putting the finish on? Would I need to key it or PVA again?

Basically, how do the pros approach a fairly rough old wall?

Thanks in advance

analhamster said:

I've removed paper which has left a rough surface, some hollows of variable size, a few holes. There's also a chase which has been filled and stands a little proud. I've knocked off all the loose stuff and sealed with PVA.

My question is, what next? Should I go straight for finish on tacky pva and use a varying thickness with the first layer to smooth the problem areas? Or put a tight coat of bonding round the lot and skim onto that? If bonding, how long should I wait before putting the finish on? Would I need to key it or PVA again?

Basically, how do the pros approach a fairly rough old wall?

Click to expand...

Not a pro, but in my humble opinion I would approach with the tight coat of bonding route, as you prob have quite a lot of variation. Some may be skilled enough to go straight for the multi to fill out the variation, but for me I would get a better skim finish if I get a uniform bonding thin undercoat first to provide a stable platform ready for the skim.

You've already PVA'd once, so apply more (tacky etc) just before doing the tight coat of Bonding.
then once the Bonding has darkened it can be immediately skimmed requiring no PVA etc.
Skim coat applied in two layers as usual.