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Painting & Decorating

How to prep a wall before painting

I have just removed wallpaper from a room using a steamer, while removing it seems it was previously painted a very dark blue before the wallpapering was done, it doesn’t seem that the wall was ever primed etc just painted directly onto the plaster so it has left the room with some areas exposing just the plaster while other parts still with paint. It seems that the paint has been layered quite thickly so I am left with a map like effect on the walls. Is there any other way to deal with this other than sanding? As to do this would be quite labour intensive due to the thickness of the paint applied & if possible I would like to avoid the route of lining paper, is there a way to perhaps thin the existing paint so as the edges were not so impressionable before priming/painting? Or anything else?
Thank you for any advice that can be given.

4 Answers from MyBuilder Painters & Decorators

There are no shortcuts to a good job. If the surface is rough and uneven sand with 40 grit, wash over and apply 1 thin coat of emulsion.


Answered 5th Feb 2020

This is a very common problem when removing wallpaper from the walls because you never know the state of the wall behind it. In your case you've got 2 options; sand down with a very gritty paper like 40g - 60g and mix some powdered filler (easyfill) and start filling uneven surfaces and than re-sand with a finer paper like 120g and then apply a thinned down coat of super matt emulsion (do not use vynal or silk paints).

Or you could go with option 2 which is always my most preferred option and find a plasterer and get him to skim the walls with a thin coat of multi-finish and once dry apply the thinned down coat of paint. This saves you from filling and sanding for a couple days and a newly skimmed surface will always look better and cleaner than a sanded and filled old surface.

I hope this helps.


Answered 5th Feb 2020

I always put up lining paper on any walls that have been previously papered. Much better job and without any of the potential problems


Answered 5th Feb 2020

Peeling and scraping off layers of old wallpaper can leave the walls beneath covered in adhesive. Worse, it can leave them pitted and scarred from your attempts to remove every last shred of paper. Before you can paint over these wounded surfaces, you must return them to perfect smoothness. As with most finishing jobs, preparation is key for painting, and the quality of your paint job depends on the time and effort you put into patching and sealing.


Answered 5th Feb 2020

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