![]() 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. ![]() 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. A Word About LVL Grades LVL USER’S GUIDE 3 WEST FRASER TIMBER Product Line 4 Storage, Handling & Installation 4 3100Fb2.0E WEST FRASER LVL 5 1³ AND 3¹ THICK Design Properties 6 Factored Resistance Table 7 8 Multiple Member Connections 9 3000Fb1. Live load point load kN The imposed point live load that can occur anywhere on the span or the overhang. Chapter 8 also provides requirements for the application of ceiling finishes, the proper ventilation of concealed spaces in roofs (for example, enclosed attics and rafter spaces), unvented attic assemblies and attic access. 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). Loads are calculated in accordance with Table 3.1 of AS/NZS 1170.1:2002. Allowable span tables are provided to simplify the selection of rafter and ceiling joist size for wood roof framing and cold-formed steel framing. The primary purpose of this publication is to provide a convenient reference for joist and rafter spans for specific grades of Southern Pine lumber. Forest Products Machinery & Equipment EXPO.Headers & Beams : Allowable Load Tables.Headers & Beams : Size Selection Tables.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. Flat Loading: 1.15kN/m2 Dead Load + 1.5kN/m2 Imposed Load. House Loading: 0.75kN/m2 Dead Load + 1.5kN/m2 Imposed Load. Once these have been entered, the joists suitable for this application appear in the table below. 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). This application will specify a list of acceptable JJI-Joists once you enter your support conditions, load case and clear span. 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. Note: Snow load factors can be specific to the regional location of a structure. Rafter Span Tables Rafters with ceiling not attached to rafters, live load = 20 Psf, dead load = 20 Psf, deflection limit L/180 In US, most wood rafters have maximum length of 20. Rafters are usually made of pine or cedar tree, for longer span rafters, building materials several manufacturers have created Laminated veneer lumber (LVL) rafters that can be 25 times longer than typical wood rafter. 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. Many species of wood are used to provide timber which have much strength. Note also that you can break up the span of a rafter by adding a purlin and bracing to the underside. When calculating the maximum span of a rafter, use the horizontal distance between two vertical supports. ![]()
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