noggings between ceiling josts

hi there, I am renovating/converting and old house and barn and have built a load bearing wall to carry the first floor joists. These are 150 x 250 chestnut beams which I have needed to space on roughly 800 centres across a 4metre span. I know these centres are a bit too far apart but I only have a limited number of beams. My plan was to infill with timber noggings to support the 16mm osb flooring and to create a fixing for the plasterboard that will go between the beams. Obviously as the beams will be exposed I don't want to cover them up too much so my long winded question is..... what is the smallest size nogging that would be of any worthwhile value. I was hoping to get away 50-60 mm? any comments gratefully received.

60 mm won't do anything.

3/4 of the depth is the minimum

And you are asking a lot for 16mm OSB to span that width. Even plywood would struggle, and 22mm T&G chipboard would be at its limit

thanks for the comments. I don't have the required depth so will have to make do. If i go to 75 mm i will be half depth and perhaps I can increase the width to say 100mm. I planned to space the noggings on every joint and in the middle of every board, ie 300mm centres ( the osb is 2000 x 900 t & g) . Fingers crossed.

The purpose of noggins is to stop the top/bottom of the joist twisting, and to stop individual joists moving [downwards] - thus making the floor act as one.

So increasing the width of a noggin is not going to do anything.

But on second thoughts, is a 250mm wide joist goings to twist? Probably not.

I'd space the noggins at 450 centres though - 300 seems excessive.

Are the noggins to be just skew nailed or notched or such-like? THe may want something better than a couple of nails if they are going a big part in supporting the flooring

Ok, thanks for the advice Woody, The beams are a couple of hundred years old so have probably twisted all they are going to already. I don't really have any concerns about them, as you said its the osb i'm trying to support. The noggings will be notched and fixed with large screws. 450 centres sounds good to me as notching 300 centres would be a weeks work for me! Thanks again for your help