Decorating plasterboard is not so different to decorating new plaster other than the preparation required to get brand new boards ready for painting. For the answer to the eternal question, which side of the plasterboard should I paint, please scroll down.
If new plasterboard walls were built to be painted or decorated, rather than plastered, boards called Tapered Edge boards will have been used. The edges of the board taper in slightly to allow the joint to be filled in such a way as to stop any lumps or bumps showing through paint or under wallpaper. The joints in the boards are filled by first taping over the joint with a vertical strip of joint tape< which can be bought below in our tool store. This is then covered with a special joint filler available from builders merchants and some DIY Sheds. For the best finish we always recommend applying the joint filler in two layers. The first, with a small filling knife, working the filler into the joint and finishing with a seam or strip of filler about 5mm either side of the joint.
When this is dry, use a jointing knife to fill the taper and leave the filler as flush as possible with the surface of the boards. This is sanded down when dry using a fine grit sandpaper. A 12 inch ruler can be put onto the board, horizontally across the joint, and by moving the ruler up and down the joint you will be able to see if any of the filler has sunk below the level of the board or is sticking out, proud of it. Add, or sand off, filler as required.
The plasterboard should then be painted with a mist coat of the emulsion you intend to use. This is a dilution of the paint to 4 parts paint to 1 part water and will allow the board, and joints, to be primed before painting with the undiluted paint. It will not harm the board to do two mist coats before painting with undiluted emulsion.
If you plan to wallpaper the wall, then these mist coats will work as well to seal the board prior to pasting or you can size the boards with a sizing solution just as you would an ordinary plastered wall.
It could be that your wall is in bad condition, so before you decorate you might need to skim plaster the wall first. You can find out how to do this by clicking on our relevant project.
Despite a million posts in various forums and different opinions coming from every direction we can clearly state on this website that it does not matter at all which side of the plasterboard you paint on and which side you plaster on. The ivory side of normal plasterboard is a little smoother than the brown side. This makes it a little easier to get a good finish when decorating but the difference is barely noticeable. Thistle Multi finish plaster and board plaster will stick like glue to either side and if you want to check this out then please feel free to ring Lafarge. They will tell you exactly the same thing.