Roof Joist Vs Roof Rafter

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.

Roof joist vs roof rafter.

In traditional timber they are nominally 2 inches thick and typically 8 to 10 inches wide. Rafters are made from sloped framing boards of dimensional lumber usually 2x8s or 2x10s connecting the roof peak called the ridge board to the plates of the exterior walls. 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. Our roof rafter calculator tools are handy for calculating the number of rafters needed rafter length calculator lineal feet of rafter board feed in ridge and sub facia and the total board feet in the roof.

Conventional framing the first thing to understand is how a roof framed with wood i joists differs structurally from a traditional stick framed roof. If you live in an area that requires a shed roof rafter to support a heavy load then an spf rafter can only span 7. However in canada the most common material used in residential framing is wood so that is the material we will discuss here. Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.

Both of these are for light roof loads. 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. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. An syp rafter can span 11.

They are secured at the bottom by ceiling joists. Collar ties placed horizontally halfway down the rafters hold the rafters and roof planes together. 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. Visit the roof framing page for more information on cutting roof rafters and visit the roof pitch calculator for determining rafter lengths based on rise and run.

As mentioned above a 2 4 spf shed roof rafter can span 11. 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. Rafters are the building components that run diagonally from the wall plate to the apex of a roof structure.