The message
from "Suz" contains these words:

The idea is to have real strudy floor to minimise any bend and noise
transference. The longest one will be in the roofspace and as the
kids will
be there I want to reduce the elephantitis noise from above.

Oh, none of the strenghening will do that. In fact a stiffer floor may
well transmit sound and vibration better than a more compliant floor.

What you want is a /soundproof/ floor - that's a different thing altogether.

--
Skipweasel
Pay no attention to that man behind the curtain.