Nailing Down

• The most common method for installing hardwood flooring of any type involves nailing the planks to a plywood subfloor, says the World Floor Covering Association. Special flooring nails are used along with a flooring mallet to prevent splitting in the planks from excess vibration. Nailing down works best with planks that are solid wood, not with flooring that is made from engineered wood. Squeaks eventually develop as nailed flooring shrinks.
  
  

Stapling

• A large pneumatic stapler is used to drive the 2-inch-long staples that are used to secure wood flooring to a graded plywood subfloor. These machines make quick work of installing hardwood flooring but must be rented from a home improvement store due to their high price tag, according to Hammer Zone. Floor-stapling machines are safe because they rest directly on the floor. Staples can also cause noise issues as the hardwood flooring ages.
  
  

Adhesives

• If you'd prefer not to remove the existing tile or wood flooring, adhesives allow you to install your new wood floors over them. As long as the subflooring and current flooring material is sound and smooth, the adhesives will adhere correctly. Vapor barriers are required with this method, states Consumer Reports. The glue itself, along with the existing flooring, is a sufficient barrier against vapor from the concrete subfloor. New plywood subflooring is also compatible with adhesives.
  
  

Floating

• Floating planks lock together and rest on top of another flooring material or a cork pad. No fasteners or glue is used to attach them to a subfloor. Only engineered wood flooring is suitable for this installation method, says Home Time. A plastic vapor barrier must be laid below the cork or foam pad that cushions the floating planks. Without this cushion, most floating hardwood floor systems shift as they are walked over.