How to Clean Hard Wood Floors Enhance First Impression » You will find three main types of floor structures, generally used in modern construction. Included in these are framed, truss flooring surfaces How To Clean Hard Wood Floors and created joist systems. Of all, the most commonly installed flooring system are framed floor surfaces. They consist of dimensioned lumber, bearing on external surfaces and interior load bearing wall surfaces or beams called “floor joists”. Generally the floor joists are installed, spaced 16″ aside. Putting in rim and trimmer joists, to which the floor joists are nailed, surface finishes the perimeter.