Trusses are the major engineered wood component used today, with 63.7% market share for roof trusses and 31.7% market share for floor trusses. The repair and modification of metal plate connected wood trusses can be a very complicated subject, because each situation must be analyzed individually. It is important not only to calculate an adequate repair or modification, but also to ensure that the repair or modification can be performed in the field. The truss designer needs to obtain as much accurate information as possible, by asking questions about what damage occurred and how. In simple scenarios, this may involve a redline Truss Design Drawing or photos of the damaged truss; with more complex damage or modification requirements, this may even involve visiting the site. This research report will give an overview of the fundamental principles behind truss repair that inform the truss designer’s approach in all truss scenarios. 

One source of confusion within the wood truss industry is the difference between a truss repair and a truss modification. Truss repairs can be summed up as restoring a truss back to its original shape and strength in situations where damage has caused a change or a reduction in either. Truss modifications occur when a truss profile, loading, and/or bearing conditions must be altered to fit a situation for which the original truss was not designed. This report will cover the key concepts involved with a truss repair.