Occasionally, concerns arise about notches or holes cut in Trus Joist® (TJ) products used in continuously supported applications such as rim board.
Although rim board is generally not required to span a distance while supporting the vertical load like joists and beam members, it is a critical structural component. Rim board products do much more than simply provide closure to the ends of the joist bays; they are primary structural members in the floor or roof system. Rim board products perform several critical structural roles, including the transfer of vertical and lateral loads around I-joist framing, support of deck ledgers, and lateral bracing of joists.
Although rim is a critical structural member, it generally is fully supported by the wall below instead of spanning. For this general usage, occasional holes and/or flange notches are usually acceptable. Dimension lumber band joists are often cut for wiring holes, air ducts, etc. From a building code standpoint, these modifications are not addressed. The criteria for judging continuously supported TJ products should be similar to that used for continuously supported dimension lumber; i.e., occasional small holes and notches have little impact on the product function provided there is not a large point load located above the hole.
Likewise, notches in the flanges of continuously supported TJI® rim joists are often permissible. Joist flanges resist bending stresses when a joist is spanning from one support to another. When joists are continuously supported the flanges can be occasionally notched because the joist is only transferring vertical loads.
For information specific to holes in continuously supported TJ® Rim Board, TimberStrand® LSL, TimberStrand® LSL Rim Board, and TJI® rim joists see Guidelines for Notches in Rim Board TB-224.
You can find additional info on rim board here- WIJMA - Rim Board Products for Use with Wood I-joists
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