The builder installed hard wood floors on a pressed wood sub-floor. The floor is poping in sections. I am planning on removing the section in the kitchen that is poping, replacing it and installing another 600 square feet of hard wood floors. I was told today by a hardware store that hard wood floors won't hold on pressed board. Is this correct? If it isn't, what kind of preperation do I have to do to the pressed wood to make sure that hard wood floor stays down correctly and doesn't pop?