Roof Joist Vs Roof Rafter

The main difference between joist and rafter is that the joist is a horizontal structural element transferring load from flooring to beams typically running perpendicular to beams and rafter is a structural members in architecture.

Roof joist vs roof rafter.

Rafters are the building components that run diagonally from the wall plate to the apex of a roof structure. If you have a simple gable shed roof then using 2 4 rafters makes more sense unless you have a very large shed. Rafter boards are fastened to the ridge board at the peak and the top plate where they join the wall. The boards creating the slope of the roof are wider than lumber used to build trusses 2x8s 2x10s and 2x12s are most common in rafters vs.

However in canada the most common material used in residential framing is wood so that is the material we will discuss here. For roofs that will experience heavy snow or wind and will span the same distance use 2 6 rafters. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. In a typical roof framed with dimension lumber the rafters rest on the exterior wall top plate at the lower end and bear against a ridge board at the top.

Rafters form the foundation for attachment of the roof boards onto which the final roof covering is fixed. Roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber spacing dimensions load and slope. For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters. This structural support comes in the form of roofing joists ceiling joists rafters or trusses and can be made from a variety of materials including wood metal reinforced concrete etc.

In traditional timber they are nominally 2 inches thick and typically 8 to 10 inches wide. In finished space insulation is placed between the rafter boards and drywall or other material is fastened to the face. Rafter span tables use these tables to determine lengths sizes and spacing of rafters based on a variety of factors such as species load grade spacing and pitch.