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. 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.. Floor joist span use this table to determine the maximum lengths of floor joists based on species of lumber, joist spacing, and joist size. roof rafter span use this table to determine the maximum lengths of roof rafters based on species and grade of lumber, spacing, dimensions, load, and slope.. Roof rafter, joist and beam design part 4 of residential structural design tutorial. on this page we will explain how to design with roof rafter span tables and how to read all types of joist and roof span tables for residential framing..
Span tables and other software resources from industry groups and manufacturers that assist in designing construction in compliance with codes such as as 1684. primary design software program includes generic span tables for various building elements (excluding verandah beams) enabling users to select sizes and load conditions to generate suitable member sizes and grades.. Table 9.1 in span tables for joists and rafters (figure #5) gives a required compression value of 237 psi for a span of 16 feet and bearing length of 1.5 inches. (the tables permit a bearing length of up to 3.5 inches, but since 1.5 is probably the worst case that you�ll encounter for joist or rafter bearing, it�s a safe value.). Rafter sizing for a shed roof. rafter sizing for a shed roof (post #108281) joe g on tue, 05/05/2009 i want to use 36 inch centers for the rafters and the span is 16 feet with a 2/12 pitch. one side will fasten to the house and the other will sit on a support beam. has anyone ever come across a spanning table that doesn't require.