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Bridging

1-11. Bridging

When the joists are used over a long span, they tend to sway from side to side. Therefore, bridging is installed. Floor frames are bridged for stiffening and to prevent unequal deflection of the joists. Bridging enables an overloaded joist to receive some help from the joist on either side of it. A pattern for the bridging stock is obtained by placing a piece of material between the joist, then marking and sawing it. There are three types of bridging: solid, cross, and compression.

a. Solid. To provide maximum rigidity to the joist, use solid bridging. The bridging is offset to permit end nailing where posible (see Figure 1-21 ).

Figure 1-21. Solid bridging

b. Cross. Wood-cross bridging is used most often. It is cut to ft diagonally between joists (see Figure 1-22 ). Each piece is nailed to the top of each joist before the subfloor is placed. The bottoms are left free until the subfloor is laid. This permits the joists to adjust themselves to their final positions and keeps the bridging from pushing up the joists and causing an uneven floor.

Figure 1-22. Cross bridging

c. Compression. Use hammer blows to install compression bridging. Where the bridging is drilled, it is nailed in place (see Figure 1-23 ).

Figure 1-23. Installation of cross bridging

Curriculum design: David L. Heiserman
Publisher: SweetHaven Publishing Services