I'd like to install prefinished 3/4" solid wood floors in my house but have been stymied by 3/4" p. board underlayment in all but the kitchen. I have 5/8" CDX subfloors and see these as my options ... 1) give up on a nail down install and go floating (don't want to mess with glue) ... 2) remove underlayment and nail to the existing subfloor .. 3) remove underlayment and replace with suitable material for nail down installation. If I go with #2, I will have to saw out the CDX underlayment in the kitchen as my wife doesn't want an elevation change change from dining room and foyer into kitchen. Also, I'll probably end up adding some blocking since the most asthetic oriention of the flooring has me going parallel to the joists. Option #3 has the added expense of more plywood and also a thicker floor which will probably require messing with three exterior door thresholds. I just can't get comfortable with the look of the longstrip solid wood products that allow for a glueless installation. Maybe I better try harder. What say ye flooring wizards?

Well, I committed a message board mistake by not reading existing posts very carefully prior to posting my message. There is a thread further down the list that addresses most of the issues I'm dealing with. It would seem that pulling up the particle board and putting down a replacement layer of CDX would be the way to go. That way, I'll only have to saw around the bases of some builtins we installed a while back. Fortunately, the bases are perpendicular to the joists so there should be plenty of support.