THE BASICS · DAY 004 / LESSON 3
Beginner question: what should I check about rafters?
Star defines a rafter as the main beam supporting the roof system. [1][2]
A rafter is distinct from a purlin; purlins support roof covering between primary framing.
Identification exercise
Trace a roof panel to its purlin, then to the primary rafter. Those three names refer to different roles, even if all are steel.
Start by separating the definition from the dimensions or requirements on a specific project. The reference below provides a concrete fact, its limits, and a practical example.
Sources & scope
- Star Building Systems — Metal Buildings 101: Glossary ↗
Terminology definitions.
- Star Building Systems — Secondary Framing ↗
Girts, purlins, and eave struts.
Source content checked October 14, 2026. Worked examples use stated assumptions; they are not project designs, prices, or site-specific requirements. Code editions and manufacturer specifications are identified so their limits are clear.
View the complete source library →The day is part of the BeamWerx learning curriculum; it is not a publication date.