Rafter Span Roof Span Tables

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Rafter span roof span tables.

This is set by the roof use you selected in the previous screen and cannot be modified. Loads are calculated in accordance with table 3 1 of as nzs 1170 1 2002. Live load is weight of furniture wind snow and more. 1 psf lb f ft 2 47 88 n m 2.

Dead load weight of structure and fixed loads 15 lbs ft 2. The figures are based on quality materials. Rafter spans can be extended slightly beyond what the rafter tables suggest when there is a cantelever extending beyond the supporting wall. The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter.

Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings. 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. Span calculator for wood joists and rafters also available for the android os. Rafter spans for southern yellow pine douglas fir and eastern spruce.

For pitched roofs flat roofs and ceiling joists. 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. These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center. 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.

Tables 2l and 2h list the sizes and spans for pergola or carport beams in low wind speed and higher wind speed areas. The tables below give maximum spans for rafters and beams. Also available for the android os. Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.

The imposed uniformly distributed live load in the main span. 1 ft 0 3048 m. 1 1 based on the horizontal projection of the roof rafter span. 2 are indicated below.

Keep in mind that these are maximums in other words shortening spans slightly will result in a more solid structure. Surveyors span tables for designing roof rafters. 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. For lesser grades spans should be shorter.