We are getting some work done on a new shop, the builder who is doing the work has advised us that the fireproof plasterboard he has fitted will not need to be skimmed, is this correct or does anybody think that he is trying to cut corners and save himself some money?
If it is single thickness fireproof board (pink) then as a smoke break yes it requires a single joint coat.
If however it is double thickness STAGERED joints (grey or pink) then no you don't.
The theory is that if the smoke can pass through the joints then the board won't last. If you stagger the boards on double thickness or apply only a single coat of dry lining then the smoke risk is iradicated.
To confirm you shouldn't see light through your firebreak. This is usually used on multiple story commercial buildings or more commonly a shop with flats above etc.