Is there any benefit to adding blocking (cross-bracing) between the joists in the middle floor structure? I have about a 3.5 m span and 2"x9" floor joists spaced 60 cm apart. The surface will be chipboard flooring and vinyl click-flooring.
The floor becomes more stable with cross braces in the middle, but the effect isn't as significant if you are gluing the particle board to the joists as it somewhat serves the same function. So it's a bit better but maybe not worth it, 9" and 3.5m span is okay without.