Roof Framing Spans

1 in 25 4 mm.

Roof framing spans.

The tables below give maximum spans for rafters and beams. For instance a 4 12 pitch denotes a roof rising 4 inches for each 12 inches. Pitch for a gable roof the most common is generally 1 4 or 1 3. Also available for the android os.

Rafter and joist span faq the lengths and sizes of joists vary depending on the species and quality of the lumber used. Pitch also has its own denotation determined by the rise in inches in 12 inches. 1 ft 0 3048 m. 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.

Allowable limiting heights spans contact clarkdietrich technical services at 888 437 3244 for any questions on tables below. 1 psf lbf ft2 47 88 n m2. Fill in the parts of the formula that are already known. In the example the beam spans the 10 foot width of the roof.

The spans in this table are based on a maximum supported rafter span of 16 feet where the supported span is the total horizontal distance spanned by the roof rafters divided in half not the diagonal distance or the length of the rafter. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. 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. 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.

Rafter spans for southern yellow pine douglas fir and eastern spruce. The calculated spans assume fully supported members. 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. The total load is 4 000 pounds.

Live load is weight of furniture wind snow and more. Live load 20 lbs ft2 956 n m2 maximum span ft in nominal size. Which is equal to 1 4 or 1 3 the total span of the building not counting any overhang. Span calculator for wood joists and rafters also available for the android os.

Interior framing use iprostud in clarkdietrich itools to quickly lookup the interior framing system you need. These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center. Dead load weight of structure and fixed loads 15 lbs ft2. Range of values in the tables provides allowable spans for all species and grades of nominal 2 inch framing lumber customarily used in construction.