The first time I used wood I-joists was in a floor system set into a shelf in the foundation wall. We wanted to avoid using sawn lumber, which might shrink and cause problems, and engineered lumber fit the bill. We learned a lot about wood I-joists on that job — and spent a lot of unbudgeted time doing it. But in the end, the dimensional stability of wood I-joists and their resistance to deflection convinced us to keep using them. Wood I-joists take some getting used to. While they perform better than sawn lumber in most cases, wood I-joists require special attention in handling, cutting, fastening, and bracing. Here are some of the things we've learned in five years