hi all,
1, which side is for plastering ?
2, what's the physical difference in the sides ?
thanks

The opposite side to the one that says plaster on other side. Sorry couldn't resist that...Generally now the "grey" side that used to be for plastering on years ago is the back of the board, but now the white side is used for skimming. I have sometimes put plaster board up the wrong way round (ie. heads of windows or doors etc.) by mistake and didn't notice till its all glued or screwed (its an age thing, ) but still skimmed it and its been ok ,so skim on the whiteside....

I just phoned Britsh Gypsum and apparently the paper on the side to be plastered has a treatment not given to the other side.

The white side wraps around to the other face, the dark side in theory could delaminate as it does not wrap around, in practice though it's rare.
So white side out for plastering.