Engineering wood I-joists (TJI, BCI, AJS, etc…) are a popular choice for floor framing members in wood-frame construction, and we like them for the same reason others do: they are very efficient structural members, meaning they carry a lot of loads compared to their own weight. And since they are made from engineered wood products, they are straighter and truer than natural, conventional wood (2x lumber). We often specify them as floor joists, and when screwed and glued to the floor sheathing, they provide excellent resistance to vibrations often caused when people walk across a floor.
While they are great under bending conditions, they are less efficient resisting tensile loads. Some manufacturers, such as Weyerhaeuser, have tested their joists and determined that they are strong enough to use as tension ties for common gable roofs, so long as the ends are blocked as detailed in one of their technical bulletins (click here to read).
With that in mind, this is not true for all I-joist brands – some explicitly say that their product may not be used if subjected to tension. Before using I-joists, be sure to know if and how they can be used as a tension member! Of course, if you have any questions, give one of our engineers a call today!