Floor Joist Bridging Code

The load sharing element is typically considered to be the floor diaphragm.

Floor joist bridging code. 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. Purchase the type of lumber that matches the width of the existing joist. 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. Trus joist tji joists are made with no observable twist and have minimal material variation between joists within any joist series depth.

However some people add additional bridging to try and stiffen the floor and provide additional load sharing or to brace the joists per nds 4 4 1. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures. 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. Floor joist bridging is critical to the structural strength of a floor as shown in figure 1.

The code does recognize load sharing through the value of cr. Consequently they do not see any significant benefit from bridging. In addition to providing lateral support blocking helps transfer weight to adjacent joists so that the floor acts as a unified system. Our code report icc esr 1153 specifically states that bridging is not required for floor and roof tji joist applications.

Measure the width and length of the existing joist. But local building codes should always be consulted since unusual situations may call for different span recommendations. True floor joist span calculations can only be made by a structural engineer or contractor. Additional support for the floor joists is achieved by nailing the ends of the joists into headers.

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.