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The Importance Of Floor Joist Bridging - Part 2

Part 1

Bridging should be installed between floor joists in both indoor and outdoor applications including decks.

A common mistake, when installing solid bridging, is to offset the bridging, as shown in Figure 5.

The reason the bridging is nailed in this manner is because it is easier to nail the bridging to the floor joists. However, it is not the nails that truly provide the transfer of the load and prevent the twisting and warping of the floor joist. It is the strength of the bridging material itself.

correct and incorrect installation of solid bridging
Figure 5 - Correct and incorrect installation of solid bridging

In order to nail the solid bridging into position without offsetting every other piece it is necessary to use angle and toe nailing techniques.

As shown in Figure 5a the first piece of solid bridging is toe nailed into the farthest floor joist. The toe nailing technique would have to be used on the first piece of solid bridging even if you were to offset the solid bridging pieces.

  • Two nails should be applied on opposite sides on the top and on the bottom of the bridging toe nailed to the first floor joist.
  • Two nails should be applied through the second floor joist into the end of the solid bridging - one at the bottom and one at the top.
nailing first piece of solid bridging
Figure 5a - Nailing first piece of solid bridging

Once the first piece is in place the next pieces are nailed on an angle through the floor joist and into the solid bridging as shown in Figure 5b.

  • Two nails should be applied on an angle through the second floor joist and into the end of the solid bridging. One on each side top and bottom.
  • Two nails should be applied through the third floor joist into the end of the solid bridging - one at the bottom and one at the top.
nailing subsequent pieces of solid bridging
Figure 5b - Nailing subsequent pieces of solid bridging

Toe nailing will have to be utilized to secure the solid bridging to the last floor joint, in the same manner as nailing the solid bridging to the first floor joist.

When installing cross bridging, the bottoms and tops of the cross bridging lumber should be directly opposite each other, as shown in Figure 6.

correct installation of cross bridging
Figure 6 - Correct installation of cross bridging