Floor Structures

A floor structure supports the weight of the occupants, furniture and other items. Floor structures in single family homes are most often constructed with concrete or wood. Larger buildings such as condominiums and commercial structures often use concrete or steel. Floor structures are often covered or enclosed by interior finishes, such as carpet on top and drywall at the ceiling below. This can make problem or capacity analysis more costly and difficult.

Besides supporting the weight of the people and items in the home, a floor structure may also serve as a structural diaphragm. This is a structural component usually orientated on a horizontal plane which collects and transfers horizontal (wind, earth, etc.) loads. Generally speaking, exterior walls and roof surfaces orientated perpendicular to the direction of wind (and other horizontal loads) transfer these loads to the diaphragm (roof or floor structures). The diaphragm then transfers that load to shear walls. These are walls that orientated parallel with the horizontal load. Shear walls then transfer the loads to the foundations. Thus the load path for a horizontal load against the structure is completed.

As with any structural component or system, problems may arise from improper construction, damage, or deterioration of a floor structure. Problems may also arise if a floor structure is loaded beyond its capacity. This can occur when heavy objects (pianos, water beds, etc.) are placed over an already marginal floor structure. Some common problems with floor structures and potential causes are presented in the Common Problems tab at left.