How do I remove emulsion paint from walls that have not been primed?

The way to have painted new plaster is wash the walls with plain clean water to remove dust and apply three coats of water-based emulsion. The first coat thinned out to the consistancy of skimmed milk and preferably applied with a brush. This mist coat soaks into the plaster and takes a grip. Then you apply two further unthinned coats with a roller if you like. Even when you do it properly you will often get areas where bits do not stick, either because the plasterer was overtrowelled and made the skim coat dense or there was some dust or residue acting as a barrier. Just strip back the loose areas and apply a thinned coat of emulsion. Be careful not to scratch the plaster if you use abrasive paper. There is primer nowadays for new plaster and a lot of DIYers and especially Americans falsely think you must use it even on previously painted walls. This is not true. It is completely unecessary, but it can be useful on problem walls, for example if your plasterer had completely ...  more