Pre-engineered metal building secondary framing (per the MBMA Roof Framing Design Guide) is a three-part trio: purlins run along the roof between primary frames, girts run the walls, and the eave strut closes the transition between them. The buyer is a PEMB manufacturer — Butler, Varco, Nucor, and the regional builders — running an in-house roll line or sourcing from a contract manufacturer.

Cee and Zee profiles dominate secondary framing. The line that ships both, with quick changeover between sections and gauges, is the line that handles the customer's SKU mix. TEKFAB has shipped PEMB-class secondary framing lines on the Heavy Gauge Structural envelope and on dedicated Cee/Zee custom builds.