Just started decorating the new flat I have just built. Thought of another tip if you want to seal new plaster board for any reason PVA Glue is the thing to use. We were put onto this by a builder friend (yes the stuff we used in play group!) you buy it from builders merchants in a big bottle and paint it on like paint. We are doing the walls and ceilings and you can put it on with a roller and do the edges with a brush. It drys really quickly and then you can get right on and paint.