Which component is known as the angled member of a roof frame?

The correct answer is the rafter, which serves as the angled member of a roof frame. Rafters are crucial in creating the slope of the roof and are typically arranged in pairs, running from the ridge or peak of the roof down to the eaves. Their angled design allows for effective water drainage and snow runoff, preventing accumulation that could impose undue stress on the roof structure.

In contrast, purlins are horizontal members that provide support to the rafters and are positioned between them, aiding in the distribution of loads. Joists are horizontal supports used primarily in floor systems, not in roof structures, while beams serve as major supports that can be either horizontal or vertical. Each of these components plays a specific role in the overall integrity and functionality of a roofing system, but when specifically referring to the angled member, the rafter stands out as the correct choice.