To calculate the maximum spans of species not shown above, use the Span Calculator or the Span Tables for Joists and Rafters on the American Wood Council website. To calculate maximum rafter spans using different design criteria (load, snow load, spacing, grade, etc.) for these common lumber species, see the International Residential Code (IRC). The span values (displayed above) are from the American Softwood Lumber standard sizes. Rafters with ceiling not attached to rafters, ground snow load = 50 Psf, dead load = 20 Psf, deflection limit L/180 The following span table uses a moderate snow load of 50 Psf, but yours could be more or less. Consult your local building code authority to determine the snow load in your area. 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. This table is simply a sample and may not be valid for your region. Note: Snow load factors can be specific to the regional location of a structure. Spruce, Pine or Fir, No.1 or No.2 with 31.3 psf of Snow Loading Maximum Rafter Span of 16 feet. Rafter Span Tables Rafters with ceiling not attached to rafters, live load = 20 Psf, dead load = 20 Psf, deflection limit L/180 ![]() The braces need to be supported by a bearing wall, shown in the diagram above.Įxample: In the rafter span table below, the highlighted cell (13-0) indicates that a 2" x 8" Douglas Fir rafter, with a grade of #2, spaced 24" apart, can have a maximum span of 13 feet - 0 inches (13-0) if designed for a live load of 20 Psf, and dead load of 20 Psf. The loads are based on adjusted roof snow loads from the governing building code. Note also that you can break up the span of a rafter by adding a purlin and bracing to the underside. Span Tables F7 Rafters A maximum roof pitch of 25 degrees is assumed. 6.OOF LOADS R Rafter spans are tabulated for the most common roof loads. applications according to the 2018 International Residential Code. Neither SFPA, nor its members, have knowledge of the quality of materials, workmanship or construction methods used on any construction project and, accordingly, do not warrant the technical data, design, or performance of the lumber in completed structures.When calculating the maximum span of a rafter, use the horizontal distance between two vertical supports. These rafter span tables provide the best reference to quickly and easily determine the maximum span for all grades of southern pine according to the 2018 International Residential Code. The conditions under which lumber is used in construction may vary widely, as does the quality of workmanship. The design values contained herein are based on the Southern Pine Inspection Bureau’s Standard Grading Rules for Southern Pine Lumber (2002 edition with supplements) and modified as required by AWC’s National Design Specification® (NDS®) for Wood Construction (2012 edition).Īccordingly, SFPA does not warrant that the design values on which the span tables for Southern Pine lumber contained herein are based are correct, and specifically disclaims any liability for injury or damage resulting from the use of such span tables. SFPA does not grade or test lumber, and accordingly, does not assign design values to Southern Pine lumber. The maximum spans provided herein were determined on the same basis as those in the code-recognized Span Tables for Joists and Rafters(2012 edition) and Wood Structural Design Data (1986 with 1992 revisions), both published by the American Wood Council (AWC). ![]() 20 Allowable Load (plf) for 3-1/2-inch Wide 24F-V4/DF Glulam Floor Beams - 100 Floor Load Span. The values are based on the design properties listed in EWS Y117 and are in addition to the beam weight (assumed 35 pcf). The primary purpose of this publication is to provide a convenient reference for joist and rafter spans for specific grades of Southern Pine lumber. Full lateral support on the compression side. The loads are based on adjusted roof snow loads from the governing building code.
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