Pitched Roof Rafter Spacing

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.

Pitched roof rafter spacing. For standard shed roof rafter spacing see rafter span chart. Surveyors span tables for designing roof rafters. If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center. For instance 2 grade 2x4s at 16 on center will span just over 9.

Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. You can use either 2 6 or 2 4 rafters for roofs with a 3 12 pitch or greater but it depends on the overall size of your shed. There is no standard spacing it depends on what size of rafters you want to use and the span of your shed.

For roofs that will experience heavy snow or wind and will span the same distance use 2 6 rafters. Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16 size of rafters in mm 400mm 450mm 600mm. Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. The spacing between rafters in a given building is part of the engineering calculations that determine the required structure of the roof.

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. Rafters must be strong enough to hold the roof sheathing and the shingles. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. Other relevant factors include the type of wood being used for the rafters the size of the rafters and the load that the rafters need to support.

For roofs that won t experience heavy snow loads a gable roof can span up to 22 with 2 4 rafters. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. For pitched roofs flat roofs and ceiling joists.