What is a rafter?

A rafter is a sloped structural roof member that runs from the ridge down to the exterior wall, supporting the roof sheathing and covering.

Rafters are the backbone of a traditionally framed (stick-built) roof. Under load they push outward at the walls, so they're tied together — by ceiling joists or rafter ties — or carried by a structural ridge beam to keep the walls from spreading.

Prefabricated roof trusses are the common engineered alternative to site-cut rafters and combine the rafter and tie into one assembly.

When rafter ties are required →