What do "fly rafters" support in roofing construction?

Fly rafters serve as an important component in roofing construction, specifically designed to provide support for roof sheathing and lookouts. These rafters extend beyond the wall framing, helping to create the overhang that is essential for protecting the building from weather elements. By supporting the roof sheathing, fly rafters assist in distributing the weight of the roofing materials evenly, contributing to the overall structural integrity of the roof.

Additionally, they play a crucial role in supporting lookouts, which are short framing members that help further extend the roof overhang or support eaves. This construction feature enhances the effectiveness of drainage and prevents water from running down the walls of the building, thereby reducing potential damage.

In contrast, other options describe components or elements of the roof structure that do not accurately reflect the specific function of fly rafters. The mention of vertical posts or main structural beams pertains to different aspects of structural framing, whereas the pitched surface of the roof relates more to the design and angle rather than direct support mechanisms.