Laying 25mm ply

[Lupen]

Folks,

Taken up the old floor and the joists are slightly out of level, probably up to 4mm... This is across the joists, not along their length. Given the 25mm ply is going to be very rigid, do I just put in more noggins to allow me to screw it down firmly" and potentially pull it to the shape of the floor, or should I use the noggins to try and make level, albeit above the joists in some cases?

Thanks in advance for any help

Paul

[Lupen]

1.5m by 3.8m are the dimensions of the room by the way... And laying three sheets (ish) 1220mm x 1500mm.

[Dave]

You should be able to make that difference up with your adhesive.. or lay the ply and use a fibre SLC to flatten the floor..

[Lupen]

Hi... Yep, not worried about the final level, as you say i can take up any slack when tiling, it more about getting the ply rock solid as a base.... But if you guys don't normally go through this bother then nor will I....

Cheers,

Paul

[TF Ed]

if there is movement in the joists, then its definately worth putting noggins in place approx every 400mm.
if the joists are solid and well packed into the wall, then you should be fine although belts and braces are gteed if you get my drift..