A fly rafter is a rafter positioned at a gable end’s overhang, extending beyond the wall to create the roof’s rake, or overhanging edge along the gable, typically supported by lookout blocks extending from the adjacent common rafter rather than resting directly on a wall the way an ordinary rafter would.
Because it isn’t directly supported by wall framing beneath it, a fly rafter relies on this lookout system to transfer its load back into the roof structure, an important structural detail that’s easy to overlook given how modest this overhang framing often appears.
The specific overhang distance and lookout spacing for a fly rafter are typically specified in the roof design, balancing architectural appearance with adequate structural support for the projecting eave.
What Does a Fly Rafter Involve?
- A rafter extending beyond the gable end wall
- Lookout blocks connecting it back to the adjacent common rafter
- Fascia board attachment along its exposed edge
- Careful sizing of the overhang for both appearance and wind resistance
Why Are Fly Rafters Important?
The gable overhang a fly rafter creates provides valuable weather protection for the wall below, shielding it from rain running down the roof surface, while also contributing significantly to a home’s overall architectural character and curb appeal. Because this member isn’t supported by a wall directly beneath it, its connection to the lookout system needs to be adequate to resist wind uplift, a real structural concern for larger overhangs in high-wind regions.
Undersized or poorly connected lookout blocks supporting a fly rafter are a documented cause of gable overhang failure during severe wind events, making this seemingly minor detail a genuine structural consideration rather than purely a finish carpentry concern.
Fly Rafter vs. Common Rafter
A fly rafter extends beyond the wall at a gable end, supported by lookout blocks rather than direct wall bearing. A common rafter rests directly on the wall top plate throughout its length, a more straightforward support condition than the cantilevered fly rafter overhang.