American Design Drafting Association (ADDA) Certification Practice Exam

The primary function of rafters in roofing is to support the roof deck and associated loads. Rafters are structural components that form the framework of the roof, extending from the ridge or peak down to the eaves. They bear the weight of the roof covering, the snow load, wind loads, and any other forces that may act on the structure. By efficiently distributing these loads to the walls of the building, rafters ensure the stability and integrity of the roof system.

While rafters do indirectly contribute to other functions, such as supporting the roof covering and providing some degree of insulation space, their primary role is to provide structural support. The ability of rafters to channel and distribute weight is essential for maintaining the roof's shape and preventing structural failure.

Understanding this function is crucial for anyone involved in design drafting, as it informs decisions regarding material choice, spacing, and the overall design of roof systems.