Standard Roof Rafter Sizes

For standard shed roof rafter spacing see rafter span chart.

Standard roof rafter sizes.

Weather you re building a shed roof or adding a dormer to your second story it is important to choose the proper size rafter. If your local building authority has a rafter spacing code you may not space rafters wider than required by code. Rafter and joist span faq. Builders aren t bound by standard rafter spacing measurements.

Rafters must be strong enough to hold the roof sheathing and the shingles. Just enter the dimensions of the roof rise and run to get started. Imposed loads roof snow load and short term point load altitude not exceeding 100m. If you get premium kiln dried lumber then you could span 10 5 with the same size of lumber and.

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. There is no standard spacing it depends on what size of rafters you want to use and the span of your shed. The lengths and sizes of joists vary depending on the species and quality of the lumber used. The standard roof truss spacing is 2.

Automatically calculate suitable rafter sizes enter a specific rafter size 1 3 timber strength class c16 cost effective for most applications. Roof pitch between 15 and 22 5 degrees with rafter spacing strength class c16 size of rafters in mm 400mm 450mm 600mm. Rafter and roof joist spacing is only one part of a complex roof design that works together to form a structure that meets building codes and can hold up the weight of the roof and roof load. 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.

This is the distance between trusses. Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches. For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine. You will also incur additional costs because it is much harder to deck and shingle a roof that is 12 12 pitch versus a 4 12 roof.

There are several variables to consider when determining the proper rafter size. This sizing guide for roof rafters will help determine what you need for your small project. For instance 2 grade 2x4s at 16 on center will span just over 9. 0 75 kn m snow load.