Overlap over painted wall

Hi,

I've re-rendered a section of an internal wall. I now want to skim it with plaster and will need to skim parts of the old wall as an overlap where the new plaster meets the old painted wall. I read Unibond PVA instructions and for some reason they say not to use it on painted walls (but it can be used on tiles... ?). Do I really need a bonding agent?

Another part of the old painted wall has several small dents in it, it looks like it was done with a hammer. Can I just fill those holes with a bit of plaster or yet again do I still need some kind of bonding agent?

Many thanks.

Do you mean that you have re-rendered in sand & cement?

What condition is the old paintwork in?

If this is not a wet wall or a wall thats previously had damp issue, then brush on two coats of PVA - allow the first to dry and the second coat to go tacky then skim.

I have re-rendered with plastering sand and Natural Hydraulic Lime 3.5 (I had some spare). The old internal walls are rendered with sand and cement, and a grey finishing coat.

The paintwork is old but sound.

I was thinking of using PVA for the overlapping but was surprised Unibond's instructions said otherwise. Since there is no damp issue, I guess it's ok to use PVA.