Purlin and rafter spacing 12 metal roof full#
Purlin and rafter spacing 12 metal roof code#

Header trusses are special order up to 24 wide. 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. Lean-To trusses are stocked in a 1:12 slope x 12 and 20 width and special order up to 60 wide.

Purlin and rafter spacing 12 metal roof code#

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. The second span table is the same as the first. The first span table is for roofs where the ceiling is not attached to the rafters (with no snow load), a live load of 20 Psf, a dead load of 20 Psf, and a deflection limit of L/180. Consult your local building code authority to determine the snow load in your area. Rafters with ceiling not attached to rafters, ground snow load 50 Psf, dead load 20 Psf, deflection limit L/180. 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 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 field you need to input are: Total load: I input 1800. The maximum span of the 2-inch by 6-inch (50 mm by 152 mm) purlin is 6 feet. This tool will tell us if the desired rafter spacing is adequate for the rafter and load.

For light-load roofs, rafters that span up to 7 23 can be used. A roof with a 24 shed rafters on center should be slanted 24 degrees. In most homes, there are three to four feet of spacing between the purlins.

Purlin and rafter spacing 12 metal roof full#

Note also that you can break up the span of a rafter by adding a purlin and bracing to the underside. Plies should be four to six feet long for metal roofs. CFSRC Information The Cold-Formed Steel Research Consortium (CFSRC) is a multi-institute consortium of university researchers dedicated to providing world-leading research that enables structural engineers and manufacturers to realize the full potential of structures utilizing cold-formed steel. When calculating the maximum span of a rafter, use the horizontal distance between two vertical supports. Attachment-Metal roof fastened directly to steel framing shall be attached by.