Floor
Floor assemblies are composed of three main framing systems: Lumber (Lumber Floor Framing System), I-Joist (I-Joist Floor Framing System), and Truss (Truss Floor Systems).
Lumber Floor Framing System
Lumber floor systems are composed of joists, girders, and sheathing:
Joist
Solid Sawn Lumber Joist - Floor joists are soild-sawn wood structural members. They typically are supported at each end by a foundation or girder. Floor joists are placed 12-in., 16-in., 19.2-in, or 24 inches on center.
Girder
Floor Assembly Girder Products - A horizontal solid wood structural member used to support and stabilize floor joists along their length. Girders used in lumber floor assemblies are site fabricated typically using multiple pieces of 2 x 10 or 2 x 12 lumber nailed together.
Sheathing
Floor Assembly Sheathing Products - The structural covering placed directly over framing members which also serves to transfer loads into the structural framing. Wood structural panel sheathing is commonly sold and installed in 4’ x 8’ sheets.
I-Joist Floor Framing System
I-Joist floor systems are composed of I-joists, sheathing, a rim board, and sometimes girders.
I-Joist
Floor Assembly I-joist Products - A horizontal structural member manufactured using sawn or structural composite lumber for flanges and structural panels for webs, bonded together with exterior exposure adhesives, and forming the cross-sectional shape of an “I”.
Sheathing
Floor Assembly Sheathing Products - The structural covering placed directly over framing members which also serves to transfer loads into an I-joist. Wood structural panel sheathing is commonly sold and installed in 4’ x 8’ sheets.
Girders
Floor Assembly Girder Products - A horizontal structural member used to support and stabilize I-joists along their length. Girders used to support I-joist floor assemblies are typically made from glued-laminated lumber, parallel strand lumber, or multiple pieces of laminated veneer lumber (LVL).
RimBoard
Floor Assembly Rimboard Products - A board that fills the space between the sill plate and the bottom wall plate, or between the top plate and bottom plate in multi-floor construction, and used with I-joist floor construction. The rim board is attached to the ends of I-joists and is used to help transfer wall loads through the floor assembly. The rim board is an integral structural component that transfers both lateral and vertical forces.
Truss Floor Systems
Truss floor systems are composed of parallel chord trusses, sheathing, rimboard, and sometimes girders.
Truss
Floor Assembly Truss Products - A horizontal engineered structural component, assembled from structural wood members and metal connector plates or other wood joining methods, designed to carry its own weight and superimposed design loads. Truss web elements are assembled such that they form triangles. Floor trusses have top and bottom chord members that are parallel. Web members are placed both vertically and diagonally between chord members.
Sheathing
Floor Assembly Sheathing Products - The structural covering placed directly over the framing members which also serve to transfer loads into the truss. Wood structural panel sheathing is commonly sold and installed in 4’ x 8’ sheets.
Girder
Floor Assembly Girder Products - A large-dimension beam used to support uniform or concentrated loads at various points along the length of a truss. Beams and girders are of solid lumber or built-up construction in which multiple pieces of nominal 2-inch thick lumber are nailed together with the wide faces vertical.
RimBoard
Floor Assembly Rimboard Products - A board that fills the space between the sill plate and the bottom wall plate, or between the top plate and bottom plate in multi-floor construction. The rim board is attached to the ends of trusses and is used to help transfer wall loads through the floor assembly. The rim board is an integral structural component that transfers both lateral and vertical forces.