hi, I am confused as to what is the best product on the market to us as sub flooring. I was always under the impression that the harder the wood the better, now I see that builders are using a type of particle board, who can this be good. The house I currently own has plywood and after thirty years squeek. What will this pressed wood do? or if per chance get wet. what should I use in the new home I plan to have built? P.S also what should be used as uder structure for the walls.