Novice - Plasterboarding ceiling at 600mm centers.


New Member
Hi all,

I'm working on a house with new posi joists at 600mm centers. We will be plasterboarding in the next few weeks. Would a 12.5mm sheet be ok or will it have to be 15mm? There are no noggins and the boards will be foil backed.



Queen Jess Elizabeth I


Private Member
The board manufacturers will say 12.5 is ok, but there is still quite a bit of flex if there is no noggin. 15mm would be better to use. Some pozi-joist are 150mm so in essence, the unsupported span is only 450mm