Floor Joist Bridging Requirements

Adding two rows of bridging costs a few dollars per joist.

Floor joist bridging requirements. What are the bridging requirements for double pitch joists. Proper bridging distributes the load on the floor to other joists and over time prevents floors from sagging and squeaking do to floor joists twisting and warping. To install the type shown here drive the toothed end into the joist and nail the other end. Additional support for the floor joists is achieved by nailing the ends of the joists into headers.

These same findings are not proven to apply to other types of floor joists i e i joists steel joists etc or for dimension lumber joists greater than 12 inches in depth. True floor joist span calculations can only be made by a structural engineer or contractor. Cut the lumber to fit between the two joists. Our code report icc esr 1153 specifically states that bridging is not required for floor and roof tji joist applications.

Floor joist bridging is critical to the structural strength of a floor as shown in figure 1. According to the study bridging may be considered necessary for 2x10 and 2x12 dimension lumber joists with clear spans exceeding about 16 feet and 18 feet respectively. Hammer your nails through the blocking and the joists. Section r502 10 of the international residential code states that header joists can be the same size as the floor joists when the header joist span isn t greater than 4 feet but if the header joist span is more than 4 feet you ll need to double the header joist and ensure that it s capable of.

This allows you to find the distance in lumber you need to cut. For any joist where the center of gravity is above the support point all rows of bridging should be bolted cross bridging. A joist manufacturer can give direction on this. Trus joist tji joists are made with no observable twist and have minimal material variation between joists within any joist series depth.

The lumber should be the same depth as the joist. From both ends of the span. Various types of metal bridging are available at home centers and lumberyards. This sample table gives minimum floor joist sizes for joists spaced at 16 inches and 24 inches on center o c for 2 grade lumber with 10 pounds per square foot of dead load and 40 pounds of live load which is typical of normal residential construction.

Consequently they do not see any significant benefit from bridging. The joists immediately under the load deflect substantially before the straps are tensioned and start spreading weight to other joists. Properly installed wood x bridging tightens as the joists shrink to the degree that i ve seen the bottom of the joists get a slight crook in them from the bridging. Measure the length between the two joists.

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. The joists shown here for example span 12 ft so we added rows of bridging 4 ft.