i want to install a nailed down 3/4in hardwood floor . however the subfloor is 5/8in particle board with plywood under that.talked to the people at the lumber center and they said to just install 1/4in luan board to the particle board and that would be fine. is this true?

No, it isn't true. Both NOFMA and the NWFA do not recommend installing a nailed down floor over particle board. The reason is particle board lacks the nail holding ability needed for a nail down floor. I've seen it done but don't recommend it. The 1/4" luan is worthless in this case. If you don't want to remove the particle board, either install a floating floor or if the particle board is well attached, a glued down engineered floor.

As Gary said!

It doesn't matter if you cover the particle board, like you have been advised. It will still fail, as the particle board is part of a sandwich. Particle board is JUNK! Floating floors and carpet, are the only flooring specified to cover particle board.

A gluedown on particleboard? Can you do that, really?

Yes, you can do a gluedown engineered over particle board. I would not do it,though.

Nailing 3/4 to particle board is a recipe for disaster. Particle board that has been under carpet can often look quite sound. That is because there has been no topside barrier to vapor transmission. As soon as you cover that stuff up,it is liable to blow up and disentigrate.

I have no qualms about taking up particle board and installing strip over the cdx that lies beneath. It is by no means the best way to do it; but it sure beats the heck out of making a turd sandwich.

Particle board has gone the way of the do-do for a reason. A good one.

I don't know about other parts of the country, but around here, particle board is commonly used as underlayment for sheet vinyl flooring on raised wood subfloors. If you look at the specs on most engineered wood floors, they do say you can directly glue the engineered wood floors to a well bonded sheet vinyl floor. Since the floor has already been covered with vinyl, the flooring will not effect the performance of the particle board. When I have encountered this situation, I try to talk the customer into removing the whole mess; down to the subfloor. When they resist (because of cost), I'll re-staple the p. board underlayment right through the vinyl and prep the vinyl (abrade) for gluing to it. You can use p. board as an underlayment for glued down engineered but it is a poor substitute for 3/8" CDX. CDX is way more moisture resistant and stable and about the same cost. I prefer NOT to glue directly to a wood subfloor but use underlayment. The reason: if that floor needs to be removed or repaired, you will be tearing the hell out of the subfloor. Much better to cut out underlayment and patch that than replacing subflooring.

You've given the best reason for me NOT proceeding to install 3/4" hardwood flooring over my 3/4" particleboard subfloor! Thanks for saving my behind.

Now the REAL Fun begins.