2 GRADE LUMBER)/Contents(ALL SPANS & SIZES WITHIN THE TABLES ARE BASED OFF OF SPRUCE NO. Span Options Calculator for Wood Joists and Rafters. With the purlin/bracing installed, the long rafter span would be broken up into two shorter spans, thus allowing the rafter to carry additional load. You can break up a long span of rafters by installing a purlin and bracing on the underside. Q 0 -1 1 0 0 0 cm 1 1 1 rg 0 0 0 RG 1 w -124.4188 294.3486 89.514 18 re B BT 0 0 0 rg /Helv 9 Tf 1 0 0 1 -119.9188 300.8627 Tm (SEE DRAWING A-2) Tj ET QĤ0 0 obj/DA(0 0 0 rg /Helv 9 Tf)/DS(font: Helvetica 9pt text-align:center text-valign:middle margin:3pt line-height:10.35pt color:#000000)/M(D:20200207124559-05'00')/Rotate 270/AP/Rect/NM(GYZFGSDYTRXCZYOW)/RC(ĪLL SPANS & SIZES WITHIN THE TABLES ARE BASED OFF OF SPRUCE NO. When calculating the span of joists or rafters, use the horizontal distance between to vertical supports. How the Parts Fit The doubled valley rafter in this drawing has. When used as a ceiling joist or a roof rafter, a 2×4 can span up to 7 3 spaced at 16, and 6 4 when spaced 24 apart. Figure 18-2 Width of Hip and Valley Rafters. So this table could accommodate a house with a total rafter span (or house width) of 32 feet. SEE DRAWING A-2)/Contents(SEE DRAWING A-2)>ģ9 0 obj>/Matrix/Length 153> common rafter, or half the span 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). Rafters, does not include hip or valley rafters.Įlevation under 600’ above Sea Level 70 lb.DRAWING A-1)/Contents(DRAWING A-1)/BS/Rotate 270/AP/NM(TSGCMPTODPZNIMZA)>Ģ9 0 obj>/Matrix/Length 149> The tables below give maximum spans for rafters and beams.
Rafter span code#
For heavy roofs or in areas with substantial snowfall or winds, call your local building department for code requirements. at an elevation of 900 feet above sea level. In areas with mild climates, patio roofs are generally designed for loads of 30 psf (pounds per square foot). When sizing structural ridge beams, and hip rafter beams remember to use the 80 lb. The charts below will give you an idea of what we will be inspecting for on a typical roof with ceiling joist located at top plate of wall. at an elevation of 900 feet above sea level. The length of the rafter is given from the long point of the ridge cut at the top down along the top edge the board to the same plumb cut on the rafter’s notch. Re: Ground Snow loads: the requirements have been raised from 50 Lb.
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