What Do Wood Floor Trusses Have Built-in to Level the Floor?

Wood Floor Framing

• Within a home’s structural design, flooring provides a bracing effect that reinforces a home’s framework. This bracing effect holds the structure intact and protects the framework from subtle soil movements beneath the foundation. Floor framing also plays a load-bearing role in terms of carrying weight from overhead floor structures. Floor framing materials include floor joists and beams that attach to wall or sill plates. First-floor structures sit on top of column supports that rest on a home's foundation. Upper-floor structures are supported by column supports or load-bearing walls. Wood trusses and floor joists consist of networks of 2-by-3s, 2-by-4s or 2-by-6s. These form the subflooring frame for the actual floor. Wood truss frames differ from floor joist frames in how the floor joists are used and arranged.

Truss Designs

• Wood floor trusses consist of multiple floor joist pieces arranged in two-sided construction with open triangle supports separating the two sides. The wood pieces that make up a truss have mechanical fasteners and connector plates that hold the design intact. In effect, the structural design of a truss produces a level floor plane. Trusses are manufactured according to a home’s framework requirements in terms of sizes and load-bearing requirements. The combined effects of multiple joist pieces fitted together in a structural design can create a stronger floor support than conventional floor joist constructions.

Triangle Supports

• A wood truss piece spans the length of a floor and requires little to no underlying wall or column supports. The repeated-triangle framework of truss engineering creates a self-supporting framework that maintains the level plane of a floor. Triangle supports consist of two chords (wood pieces) on top and one on the bottom. The top chords are supported by wood pieces that hold the tops of the triangles in place. The structural design of triangle supports provides the strength and stability needed to span the length of a floor without underlying column or wall supports.

Effects

• The more commonly used floor joist construction requires columns and/or load-bearing wall supports in order to carry the weight and expanse of a floor. And while effective, these support don’t always prevent the possible warping and bowing that occurs with floor joist constructions. The triangle supports built into wood floor trusses allow for the wood expansion and contraction effects that result from heat, humidity and cold. As a result, wood trusses can maintain their shape and form as level plane supports within a floor design.