ply flooring - noggins requirements

[helix]

hi,

trying to understand where the noggins need to go where replacing floorboards with ply.

Are they only needed when the entire edge of a sheet does not sit on a joist, or are they also needed when the edge of a sheet crosses a number of joists like this, indicated by the arrow?

If the former, why not just cut the board down slightly so the edge falls where there is a joist?

thanks,
alex

 

[theyomper]

Cut the ply so that it sits half way across the joist and insert noggins along the length so that the ply again sits half way over the noggin. Put additional noggins between the joists at 400mm centres. Screw ply to joists and leave a couple of mm between sheets, don't butt joint together. Also stagger the joints.

 

[helix]

are all those noggins really necessary? Can't you just do the joints over the joists? 25mm ply is fairly rigid.

 

[Wylie]

Your best with noggins you don't want sqeaky mice

 

[doug boardley]

are all those noggins really necessary? Can't you just do the joints over the joists? 25mm ply is fairly rigid.

the noggins stop the joists deflecting

 

[helix]

thanks. Will the joists deflect more with ply than with floorboards then?

I'll put them is because I'm sure it's the rights thing to do, but would like to understand why. There are no noggins now with the floorboards.

 

[nickj]

The best advice i can give mate is look at it when your working and do you feel comfortable with it. A lot of the time we know when were working whether it's right or not, if unsure then support the floor to be safe.

It's hard to judge when we can't see it. Really, the only person who will know how solid that floor is you. You will never get a failed installation if you cover all bases

 

[Wylie]

The ply probably won't have the t&g your floor boards will have so the joints in the ply won't have the same support