Question: What approved methods of weatherization exist for I-joists that are extended for soffit and eave locations on a roof structure? Do you need to have an enclosed soffit and eave, or can they be painted?

Answer: Engineered wood I-joists are fabricated from very high-quality dried wood components and should not be exposed to exterior conditions for extended lengths of time. Whenever wood I-joists are used in roof or floor cantilevers, they must always be protected from ambient water by means of a weather barrier.  Boxed soffits, lumber end closures, exterior sheathing, and APA Rated Sidings are examples of acceptable methods. Painting is not acceptable. If wood, metal, or vinyl lap siding are used, they must be backed by an approved building paper or weather-resistive barrier.