Span Tables - Calculate Joist, Rafter and Wood Beam Spans
Use the span tables in the links below to determine the maximum allowable lengths of joists and rafters. These tables provide maximum spans for the #2 grades of four common species of lumber (Southern Pine, Douglas Fir, Hem-fir, and Spruce-pine-fir (SPF).
Rafter Span Tables - myCarpentry
Rafter Span Tables - Use these tables to determine lengths, sizes, and spacing of rafters based on several factors such as species, load, grade, and 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.
further information on span measurements including a chart which converts horizontal distances to sloping distances, or vice versa. 6.OOF LOADS R Rafter spans are tabulated for the most common roof loads. The loads are based on adjusted roof snow loads from the governing building code. For roof live
Spans are given in feet and inches and are the maximum allowable horizontal span of the member from inside to inside of bearings. For sloping rafters, the span is also measured along the horizontal projection.
Span Options Calculator for Wood Joists and Rafters
Joists and rafter spans for common loading conditions can be determined. A “span options” calculator allows selection of multiple species and grades for comparison purposes. Read the Tutorial for Understanding Loads and Using Span Tables. The Span Calculator is supported by the Softwood Lumber Board.
Joists & Rafters - SFPA - Southern Pine
The 46 span tables below are for three types of framing members: floor joists, ceiling joists, and rafters. Spans in the tables are listed in feet and inches and are the maximum allowable horizontal span from inside-to-inside face of supports.
Span and Size Charts for BCI Joists | Boise Cascade
Learn more about BCI® Joists and our sizing software BC Calc® or view the US East and US West span and size charts.
Distances in this hole chart are based on uniformly loaded I-joists and allowable I-joist reactions without web stiffeners on minimum required bearing lengths. This chart conservatively accounts for the worst case created by the allowable simple or multiple floor spans shown elsewhere in this guide at on-center spacings of 12”,
1. These spans are based upon the SJI Specification, dated 1998. 2. Floors: Based upon 100 psf LL and 50 psf DL, the spacing of joists is between 1.67 ft o.c. and 3.67 ft o.c. 2. Roofs: Based upon 30 psf LL and 20 psf DL, the spacing of joists is between 4.0 ft o.c. and 11 ft o.c.
Span tables can be used to determine the size of a timber member of a particular strength class required for a given span. They also tell you what the maximum spacing should be between each section or timber member. Supporting permanent load (excluding self-weight of joists) up to 50kg/m2. Supporting imposed load up to 150kg/m2. Joist breadth 47mm.
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