I'm looking to do a hardwood floor in my second floor condo in Santa Fe, NM. Since it's not below grade or anything, I'm wondering if I could float an interlocking solid wood floor, or if I have to put down a plywood subfloor on top of the concrete. I have to lay down at least 6mm cork anyway (even considering 12mm), for the sake of my downstairs neighbor. With that plus a moisture barrier directly on top of the concrete, should I be safe?
Follow up: would the answer be different with bamboo flooring?
Best Answer
If you mean a 3/4" or 5/8" thick tongue and groove hardwood flooring, no, that is for nail or staple down only. Click-lock laminate flooring is made for floating installations, you may find an engineered wood floor for floating install too.
If you want a true hardwood floor, there is a nail base that I have used for below grade basements that would work in your situation for sound proofing or deadening. You will not need it for moisture barrier, nor should you need a layer of poly for the same reason. You are not installing on a below grade or slab on grade situation where the infiltration of moisture would be a concern.
The material is a 2' by 2' square of OSB with a plastic "dimple mat". It is available at the big box stores and will serve as a great nail base and sound deadening, but you will need to deal with the new height of your floors which will be over an 1 1/2" than what you have now. It will affect door clearance at the bottom and maybe cabinets.
There are engineered harwood floors for floating install. There are rolls of lead impregnated vinyl sheets that are used for sound deadening that can go down first as the underlayment. This will keep the thickness down so perhaps you will not need to cut all your door bottoms in the area of the new floor.
As a note, again, with your concrete floors being well above grade, you should not have an issue with moisture. If you do, there are bigger issues need to be resolved by the building manager first.