The Need for a Vapor Barrier

• Cinderblock buildings have concrete floors. Concrete is structurally sound and it provides a solid floor base, but it also absorbs moisture from the ground, transferring it to the inside of the building. To prevent moisture from damaging your wood floor, the first step is to install a vapor barrier. Polyethylene film, cut and laid over the concrete floor and extended up and over the bottom 3 inches of the cinderblock walls will keep moisture from reaching the wood. Seal the seams in the film with tape suitable for use on polyethylene.
  
  

Framing the Floor

• The new wood floor needs a base and treated dimensional studs provide it. Lay the studs flat against the floor on 16-inch centers. Use a hammer drill and concrete screws to attach the studs to the concrete floor. When used in this manner, the studs fulfill the role of "furring strips."
  
  

Installing a Subfloor

• Install a subfloor next. For this, you'll need subfloor glue and a screwgun, fitted with wood screws. Apply a 1/2 inch bead of subfloor glue to furring strips and position oriented strand board (OSD), plywood, or particleboard over the strips. Attach the subfloor with wood screws.
  
  

Install the Flooring Planks

• Before installing the wood flooring, attach a layer of 15-lb. felt paper to the subfloor with a staple gun. The felt paper acts as a noise barrier and prevents the squeaking that can occur if the wood floor makes contact with the subfloor.
  
  Install the wood flooring planks last. These planks feature tongue-and-groove assembly, and you will start installing them in one corner, perpendicular to the furring strips beneath the subfloor. A flooring nailer is essential for shooting headless nails through the tongue of the wood planks, through the subfloor and into the wood furring strips beneath.