Ceiling Choices

[Skavenger]

Hi,

I have built a workshop in my garden. 3 walls are OSB and the fourth is block (the garden wall).
Roof beams are 400mm centres.

This will be a cold roof so it will be filled with rockwool. What should I use to cover it. Don't really want to use plasterboard, and ply is q bit expensive. What about OSB and what thickness to stop it sagging?

Thanks

 

[foxhole]

9mm osb .

 

[Skavenger]

9mm osb .

Will 9mm be thick enough not to sag over time? Although with 400mm centres and plenty of screws I guess there won't be much to sag

 

[foxhole]

Will 9mm be thick enough not to sag over time? Although with 400mm centres and plenty of screws I guess there won't be much to sag

fine.