Overboarding ceiling

[Maboza-Ritchy]

Hi
I want to overboard a woodchip ceiling with 12.5mm plasterboard and I've chalk lined joist centres for fixing screws. My questions are:

1) Should plasterboard run 90 degrees to the joists?
2) If above is correct will the ends of plasterboard need to finish on a joist or will it not matter as there will be plasterboard above it?
3) What length of screw is recommended for overboarding with 12.5mm?

PS I intend to use the smaller plasterboard 1800 x 900 x 12.5 to make it easier to install.

Thanks in advance.
Steveo

 

[roy c]

You would be better cross battening it with 2"x1" battens, then you can work out the battens to you plaster board.

 

[Maboza-Ritchy]

Roy c,
Cross battening ceiling makes sense, thanks for that.
Would it be 2 x 1 inch roof batten timber I'd use or is there another type of timber?

Thanks again. Steveo

 

[roy c]

Yes mucka that would be the very same stuff (treated aswell) .. Make yourself a "prop" to hold your battens up while you screw them to the ceiling..