Flooring Ok could you tell me what flooring i need then if 4 x 2 is not
enough I believe that the flooring timer piecies are on a load bearing
wall on both sides...

What is the clear span of the timbers?

Assuming no heavy fixed dead loads (i.e. just normal flooring, no partition
walls). 600mm spacing between joists.

4x2 (50x97) = 1.58m
5x2 (50x122) = 2.37m
6x2 (50x147) = 2.86m
7x2 (50x170) = 3.29m
8x2 (50x195) = 3.73m
9x2 (50x220) = 4.17m

You get a bit extra span by spacing joists more closely. You get a bit less
if you have some heavy dead load.

Christian.