"Roger Mills" wrote in message
...

"David Hearn" wrote in message
...


I guess I assumed everyone would remember my other posts! I'm planning
on
boarding out the loft, and therefore need the extra joists to add height
for
additional insulation whilst hopefully providing a little extra
strength.

D


Unless they're firmly supported by supporting walls at both ends, they'll
simply add weight to the existing potentially overloaded joists - but not
strength!

I was aware of that (hence I think I've generally said 'possibly at 90
degrees'...) - I did expect though that it would spread the load more.
Whereas I could put a box down which may sit on a single joist, if the cross
joists were screwed together, then that joist is not going to move down
without bending the joist on top, which would also require the joist next to
it to bend... which would spread the weight over two joists. The question
is though is whether the boarding itself would do that anyway (though
chipboard is possibly not great at resisting being bent compared to 4x2's)
and whether the additional weight added by the joists would outweigh the
benefit added by spreading the load....

D