plastering over old plaster

[chipster]

hi,any tips on skimming onto old plasterwork?
i skim onto new plasterboard ok,looks good even when lighting shon onto it. But when i skim onto old plasterwork it seems to be flat and smooth but when its dried out and painted u can see impurfections. no trowel marks just wavey finish?
i give2 coats of pva 50/50 beforehand?
also 2 skim coats?
can i get away with one coat onto new plasterboard?

[Dan the man]

[quote="chipster"]hi,any tips on skimming onto old plasterwork?
i skim onto new plasterboard ok,looks good even when lighting shon onto it. But when i skim onto old plasterwork it seems to be flat and smooth but when its dried out and painted u can see impurfections. no trowel marks just wavey finish?
i give2 coats of pva 50/50 beforehand?
also 2 skim coats?
can i get away with one coat onto new plasterboard?[/quote]

Hi, I'm a plasterer, you can get a way with 1 coat on plasterboard, once you've put your first coat on just use a couple of handboards of the same mix to lay it down, I use this method on most walls, some people wouldnt agree and say 2 coats all the time different mix but I've always done it and it works for me.

50/50 pva is to strong, use a weak coat first then a stronger one 30/70, again some people wouldnt agree but I always let the pva dry before I skim on top, don't flatten it to quick and you dont have to throw loads of water at it neither when your troweling up, everyones different and will tell you "The real way to do it" but practice different techniques and find one that works for you!!

You might be putting to much pressure on the float when flattening if you keep getting wavey lines, remember though old plastered walls are not going to be flat so dont expect them to be flat when you've skimmed them.

[TheDoctor4]

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