Plasterboarding ceilings.

[sjl468]

Hi.
I'm fixing fire check plasterboard onto my bedroom ceiling. The ceiling is lathe and laster which i'm leaving up. Do I have to butt the edges of the boards on a joist as i would if fixing straight to joists? I thought that, due to the ceiling having the original lathe and plaster, i could just fix the boards up in the size they come in. Would fixing the edges of the boards to the original lathe and plaster be strong enough to prevent cracking down the seams?
Thanks.

 

[clout stench]

No.

You need to find and mark where the joists are and fix to them cutting to size.

 

[roy c]

Or you could counter batten them across the original joists with 2"x1" battens at 400mm centres.....

 

[sjl468]

I'll put some 2" x 1"s up and i suppose it'll add to the sound proofing from the kids in the loft room. The work in this house is never ending!!

Thanks gents.