Achieving a good paint finish on a bare wall using filler and sandpaper is a lot easier said than done, I decided to to remove the wallpaper from various walls in my home, then fill any holes or cracks and sand the walls to obtain what I thought appeared to be a smooth surface ready for painting, but as soon as I started to apply the paint it became evident that the finished look was, for want of a better word, terrible.
I overcame this problem by using lining paper on every wall and I was very pleased with the results. Lining paper is relatively inexpensive and can be obtained from most decorating suppliers or DIY stores, the rolls come in different weights, usually 1200, 1400, 1700 and 2000, basically the higher the number, the thicker the lining paper. I chose the 1400 paper to cover my walls, they were reasonably flat but had lots of knock marks and old patches of emulsion on them. I found the 1400 lining paper was easy to hang and of a suitable thickness to cover any slight discrepancies on the walls I wanted to paint. Depending on the condition of your own walls you may need to use a heavier lining paper to suit your needs.
To achieve a good wall surface on which to hang the lining paper, fill all knock marks, holes and cracks using a filler knife and flexible filler, remove any loose plaster and re-plaster if necessary (see wall plaster repair post). Go back over areas you have filled several times as I was amazed how much I had missed on the first pass. Let the filler/plaster dry hard, then sand the wall down, concentrating on a small area at a time, sand the filler level and remove any loose flecks of old paint and bits of wallpaper, this does take time to do but it is well worth the effort. I used an electric sander and sanding block to do this but you could always use a small block of timber wrapped with sandpaper to enable you to sand down using a flat surface and not your hand. Don’t forget to use dustsheets to cover furniture and floor coverings, and I would also recommend using safety goggles and a face mask to avoid breathing in any small particles of dust.
Safety tip :- Keep children and pets clear of the walls/room being sanded down to avoid them breathing in any dust present in the air. Ventilate the room by opening windows, if possible close the doors to adjacent rooms to avoid the dust spreading throughout your home.
If you have used a lot of filler or plaster to patch up the wall it is worthwhile sizing the wall prior to hanging the lining paper, size is basically diluted wallpaper paste (the dilution ratio can usually be found on the packet), this is applied to the wall to stop the filler or plaster from removing too much water from the pasted piece of lining paper too quickly and therefore reducing its adhesive properties. Sizing a wall also allows you to slide the paper more easily into position when you start papering the wall.
Lining paper is sometimes hung horizontally if it is being used as a base for wallpaper (see how to hang lining paper before wallpapering post), but as I was using the lining paper to obtain a good surface for painting I hung the lining paper vertically just as you would when wallpapering a wall (see pasting and hanging post), when all the strips of lining paper were hung in position, I allowed 24 hours for the lining paper to dry out, I then filled any noticeable small gaps in the joints between the strips of lining paper using a filler knife and flexible filler, where the joints had overlapped a little I cut out the excess paper using a Stanley/craft knife and filled the gap, again using the filler knife and flexible filler. Allow the filler to dry out fully, then lightly sand the filler surface flat, if you are not happy with the finish, refill the joint and repeat the process until the joints have a level flat finish. Now you can start to paint the wall and hopefully you will be pleased with the results. I used an inexpensive base coat of White emulsion, as the first coat tends to soak into the lining paper, then finished off with two coats of coloured emulsion using a paint brush for around the edges and a roller for the larger surface area.
Preparing the walls, filling the paper joints etc, does take quite a lot of time and patience, but the difference to the end result is very impressive and well worth all of your efforts, when I had finished my walls, several of my family members thought the walls had been re-plastered prior to painting.