Ask a Tradesman
Painting & Decorating Question
Painting onto new plaster - do i need to sand walls before painting?
We've just had our walls skimmed, and we're now ready to paint them. Some places are recommending sanding the walls before painting. Is this necessary if they've just been skimmed? Or can we go straight to the water down emulsion as a primer for the walls?
The answer to your question really depends on the standard your plasterer has finished the walls to. Sanding down the walls with a medium grade sandpaper can ensure the surface is free from any imperfections such as splashed plaster and grit/dust and ensure a good surface for the paint to adhere to. However, if the walls are smooth to the touch and appear free from any such imperfections then you should be fine to apply your mist coat.
If you do chose to sand the walls, ensure you use a medium to light grade sandpaper (such as a 120grit or above) as using too coarse of a paper may scratch and mark the walls.
I hope this helps!
Neil Bird & Son
Answered 12th Sep 2014
Hi walls should never have to sanded if they have been skimmed by a professional plasterer. The wall should be smooth like glass and shiny. If you look along from a narrow angle you can see a reflection. If this isn't the case I would recommend light sanding only where needed otherwise imperfections could show up after paint is dry.
Answered 12th May 2017
Glass finish is bad for paint adhesion and hand applied plaster will always have small imperfections
Ask any painter
Answered 29th Nov 2017
Almost always sanding required especially in corners. Use 180 grit. And Hoover as much as possible be painting
Answered 23rd Nov 2017
It is only necessary to sand the walls if the finish of the plaster is not perfect .However if you are sanding the walls use a sanding paper that is over 120 just so you make it very smooth to the touch . After , when you are happy with the walls you have to make sure there is no dust left on the walls as it might damage the aspect .Finally you can apply the emulsion on the walls and the result will be the one you hoped for .
Answered 30th Jan 2018
Hi Tom the answer to your question really depends on the quality of plaster sanding down the walls with a 120 grit sandpaper can ensure that there are no imperfections on the wall and when the walls are smooth to the touch you should be ok to apply your mist coat.i hope this helps Patrick
Answered 13th Dec 2017
I always give new plaster a quick "key" with a 120 grit sandpaper. Doing this creates a pourous surface for the paint. Then I mist coat at a 60/40 paint to water split. This will then show you any other imperfections that are visible in the wall. You can then rectify these before applying your 2 top coats. Hope this helps
Answered 2nd Apr 2018
Myself I would not sand down any freshly plastered walls but you would have to look 1st to see if there was any small imperfections throughout the wall but I would just go ahead mist coat on and I would recommend using a 60 40 when preparing your paint
Answered 7th Jan 2018