DIY Doctor UK DIY Forums

Hi,

We are looking to paint over old plasterwork which used to be wallpapered. The walls have cracks and we have started to repair them with plaster repair. However, thie big question is whether we would need to re-skim the wall completely in order to have a smooth finish, or if the wall can be just sanded and painted on directly.
The surface also looks porous, should we apply a sealant before applying the new paint?

Thanks

Seb

Hi seb963
The main problem with papered plaster is residue of paste. The surface must be very thoroughly washed, even scrubbed in order to remove it. The reason being that when wetted again by the paint, it can reactivate, swelling and taking the paint with it.
One answer is to seal the surface with Zinsser Gardz this is designed for the job. Go to a proper decorators merchants, not a diy store.
For the best job of all though, I would hang 1400 grade lining paper before painting. If filling and rubbing down have been done correctly, this should provide a near perfect finish.