A system for making joists including the steps of forming a zigzag-shaped web midsection and opposite ends adapted to fit together to provide a continuous joist web of predetermined depth and length, forming a bottom chord to extend between the opposite ends of the bottom of the web, assembling said web and bottom chord, forming a top chord, mounting shoes and plugs on the top chord, aligning the top chord with the assembled web and bottom chord, tacking an end of the web and the top chord which are in registry to maintain the alignment, and completing connection of the top chord and web to form a finished joist.