iJoist is an analysis and information utility for architects, engineers, and building designers using Trimjoist® open-web joist components. iJoist can be used during the preliminary design stages of a project as an aid for determining the suitability and performance of Trimjoist® components at various loadings, spans, spacings, and depths. Trimjoist® products are typically used as floor joists or roof/ceiling rafters in both residential and light commercial projects.