I currently am replacing severely damaged hardwood floors that were adhered to concrete by tar. I am on the upper floor of a concrete building.

We are installing new hardwood and the contractor recommended a vapor barrier and then nailing the subloor through the concrete. My concern is that this will alter the structure of the building and noise can travel through the nails, and that the vapor barrier will be compromised on an uneven surface of tar. The cost to remove the uneven tar was quoted at $7500!

Does anyone have a recommendation? Does everyone/anyone agree that nailing through the concrete will not be a problem? Thanks!

that is an accepted practice if fastening plywood to concrete.

Thank you for the response. I know this is a standard practice for the basement floor when nailed to the foundation, however I was concerned that I have a tenant below me and that it would compromise the barrier between us. He said he will be nailing 6 nails per plywood sheet, although I had read that with the foundation a lot more nails were recommended.

Does this sound like the correct amount of nails? Thanks again for the response, its so nice to have a place where experts are willing to help!

You may want to talk to someone at Ardex and see if they have a primer that will stick to tar and self level it out. Then do a floating plywood underlayment and nail to that.

Sounds like sage advice to me .The way I have done this is to use two layers of plywood , one on top of the other and with staggered joints . When you nail the flooring to the plywood, it becomes very solid and no nails penetrate the substrate.