Wood I-Joists and APA Performance Rated Rim Boards

Prefabricated wood I-joists are typically manufactured to depths that are slightly different from that of sawn lumber. This technical guide explains why engineered wood I-joists should only be used with APA Performance Rated Rim Boards instead of traditional sawn lumber rim boards.

This publication is designed for: builders, contractors, engineers

This publication details how moisture-related shrinkage in sawn lumber can create structural gaps up to 1/2 inch, compromising load transfer and potentially causing web failure in I-joists. It includes diagrams that demonstrate how engineered rim boards maintain dimensional stability for proper axial and lateral load distribution.

Published by APA — The Engineered Wood Association.