Sizing Trus Joist TJI’s
I’ve received dozens of emails asking me how you size TJI’s for a new home. Sizing Trus Joist brand TJI’s isn’t really that difficult once you understand the issues. Most people think that joists are sized based on minimum design loads. That is ultimately true, however, loading doesn’t usually govern the size you’ll select for your new home. Deflections are almost always the governing criteria in determining joist sizes in residential and even commercial applications.
First you’ll need to download the most current Trus Joist TJI Manual. The design manual contains all the span tables for different sizes and orientations of joists. The manual also includes span tables based on different deflection criteria. Also included in the manual are extremely important construction and safety details that need to be followed for a safely framed floor system.