Flooring base

[padstar]

Hi I have 2 bedrooms and a hallway where the floorboards have been removed and are in poor condition so I want to replace with new.

Is 18mm plywood OK to use screwed regularly at every joist?

Local merchants are doing a good deal on 18mm ply at the moment and I thought it would be as good as anything else. Any reason not to use it?

 

[JohnD]

It's much better than chipboard.

Put struts (noggins) under all unsupported edges.

 

[padstar]

Perfect thanks

If cut to land on joists do you need to put noggins in between joists width ways ie between 400mm centered joists? O had assumed not?

 

[oldbutnotdead]

Yes where sheets meet perpendicular to the joists, if you don't you get a bit of differential movement at the joints, gives you creaking and lines in carpet or other floor covering.
Plus nogging the floor joists (assuming there aren't any at the moment) will stiffen the floor up generally.
If you can't be ars*d with nogging you can just plate the joints with ply offcuts, they won't stiffen the floor but will stop the differential movement