Dale asks about hardwood floors over concrete.
If the concrete floor is above grade, like is common in a new condo, no problem.
If the concrete is in a basement, below grade, then you have potential serious moisture problems, and hardwood really doesn't like excessive moisture.
Generally it is not recommended to use massive hardwood in below grade applications. Simply too much humidity, or a plumbing spill, can destroy the floor.
You can use the new laminate products below grade, particularly if you have no history of excessive moisture problems. You do still have the possibility of a plumbing spill reaching this level of the house. If you use the laminate products with a pressboard base, you maybe asking for trouble. The pressboard easily swells in thickness and does not shrink back. At least real wood, like the real hardwood top on a plywood base that they call "Engineered Flooring" can withstand a lot more moisture abuse than any other type of wood flooring. With it on a floating cushion base, you also separate it from the concrete itself and give it more protection.
Basement floor drainage
Make sure that there is good drainage in that basement floor just in case there is a plumbing accident, and get the water out as fast as possible. A little swelling can be absorbed by the nature of a "floating" floor, it can expand a bit under the floor board trim and it will shrink back to it's original size.
The basic alternatives for that basement floor are:
- Delta FL, a egg carton looking material that goes over the concrete and the plywood floor goes over it. It separates the wood from the concrete and provides a positive drainage path.
- Dry Core, a new product that has the egg carton style plastic already glued to two foot by two foot pieces of OSB sub-flooring. Same action as the Delta in a different form. Compare prices.
- Rigid foam insulation glued to the floor and then a sub-floor glued to the insulation. This separates the wood from the concrete and provides significant insulation. The first two will take the chill off, this will actually give you a warm floor.
- Foam pad either floating or attached to the flooring boards. This can be used directly on the concrete or on a sub-floor. It provides a moisture and thermal break as well, although less effective than any of the first three. It can be used together with any of the first three.