Rim Board Basics

Rim boards play an important role in wood frame construction.  They serve to transfer both vertical and lateral loads from the structure above into the structure/foundation below.  Weyerhaeuser manufactures two products in various thicknesses and depths for rim board applications.  They are TimberStrand® LSL and TJ® Rim Board.

Rim board acceptability and performance requirements for Structural Composite Lumber are set by ASTM D7672.  This building code referenced standard addresses structural and dimensional aspects particular to rim performance.  The in-service depth along with dimensional stability after exposure to moisture (thickness swell, for example) are critical to desired functionality.

TimberStrand® LSL and TJ® Rim Board both meet the prescribed standard with appropriate design information shown in TJ-8000, the Trus Joist® rim board specifier’s guide.  Two other Weyerhaeuser products, Microllam® LVL and Parallam® PSL don’t meet the performance requirements of the standard.

Additional rim design information can be found here.  For product applications not covered, please consult your local Trus Joist Territory Manager.