The old subfloor was flexble 5/8 inch plywood.
Not glued to the joists and poorly nailed.
After placing a screw next to *every* nail,
I fastened 3/4 inch plywood over the top with 7,500 staples, 20#'s of screws and 30 gallons of glue
Very solid floor. No squeaks anywhere. Ready to handle the load.
KT