Preparing a room for skimming

[JDLDIY]

Hi there. I've got a plasterer coming in a couple of days to skim a couple of rooms and so I'm busy getting them ready.

The walls have been stripped of their woodchip to reveal some old paint. It comes off with a sharp scraper but would take days to do the whole room. Does it need to come off? The plasterer saw the room when it still had woodchip on and he asked me to cover the walls with a solution of 2:1 waterVA, would that do it?

Is there anything else I should do? Should I score the walls with a stanley knife or sand them at all to provide a key?

Many thanks.

 

[mchu6am4]

a layman's opinion here - he's probably right that pva should be adequate. If you really want to remove paint, then using a heat gun at low settings together with a scraper can really speed up this work.

hope it helps, ash

 

[Richard C]

I assume your plasterer wasn’t just going to skim over the woodchip! Unless the paint is flaky you don’t need t remove it; matt emulsion paint should be fine but if it’s gloss or vinyl silk, I would score the surface with a stiff wire brush (before applying the PVA) to make sure the new plaster skim can get a good key. 2:1 PVA/water mix is somewhat thicker than I use; I use 3:1 initially, let this fully dry overnight & then apply a 5:1 before skimming; your plasterer should do this immediately before he starts.

If you’ve any cracks, these need to be sorted out before skimming or they will almost certainly crack again. I put a strip of plasterboard reinforcing/repair tape over hairline cracks but if there are deep settlement cracks, the plaster needs to come off back to the blockwork locally to allow a proper repair; in bad casses, steel reinforced mesh must be used under new render or it will just crack again in a few weeks/months

 

[keyplayer]

I use 3:1 initially, let this fully dry overnight & then apply a 5:1 before skimming;

Shouldn't this be the other way around?

 

[JDLDIY]

Thank you very much indeed. Got my work cut out tonight!

 

[Richard C]

I use 3:1 initially, let this fully dry overnight & then apply a 5:1 before skimming;

Shouldn't this be the other way around?

On a very porous surface, new blockwork or plasterboard then yes but I’ve found using a thicker initial coat over painted plaster or Artex followed by a wash coat immediately before skimming gives better adhesion & allows a longer working time; it works for me anyhow!