Why would plasterboard need to be skimmed?

We plaster plasterboard in this country just for ascetic purposes. If left un plastered it would look awe full with joints and screw heads showing. In hotter countries like Australia where the plaster would dry out to quickly, they tape and fill the joints. Like we do in shop fitting as it’s cheaper. How ever, for a decent, professional finish it’s best to plaster the plasterboard.
For fire protection ceilings have to be plastered.

attic and ceilings need plaster to come straight and beautiful

It give you a better surface to paint on and it look better with no join or rough surface

It doesn't need to be skimmed but its generally preferred as it's another layer for strength,warmth etc... you could opt to tape and joint the wall instead but either are just as good a finish when done right.

Hi new plaster board does not need to be skimmed however the joints do at least need to be taped and filled. In most cases this will be a quicker more cost effective way than skimming. Hope this helps.

For duts and for and of course for a good contact with paint

Hi, they dont necessarily need to be skimmed. You could tape and joint where the boards meet, then sand the joints down to a smooth finish to the boards. Then paint it with a watered down emulsion as the first coat and then apply 2 further normal emulsion coats. Then it should be ready for your top coat of paint. Thanks

They should only be skimmed if using a square edge board. Personally i would say use a tapered edge board, and have it tape and jointed as plasterboard unless damaged is deemed a finish product