Flat Roof Joist Span Tables

These span tables apply only to flat roof and roof with a slope of up to 10 degrees.

Flat roof joist span tables. Straight line interpolation shall be permitted for intermediate spans and design values. These span tables assume installation of at least three joists or rafters that are spaced not more than 24 on center. Size of joists mm clear span c16 joist m clear span c24 joist m 47 x 95 47 x 120 47 x 145 47 x 170 47 x 195 47 x 220 1 77 2 40 2 89 3 38 3 87 4 36 2 05 2 67 3 22 3 77 4 31 4 85 assumptions at 400mm centers. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.

They also tell you what the maximum spacing should be between each section or timber member. Surveyors span tables for designing roof rafters. The calculated spans assume fully supported members properly sheathed and nailed on the top edge of the joist or rafter. Joist and rafter span tables.

Notches are not to exceed 0 125 of the depth of the joist and are to be located between 0 07 and 0 25 of the span from the support. Span tables use the span tables below to determine allowable lengths of joists and rafters based on size and standard design loads. Listed are 46 tables based on common loading conditions for floor joists ceiling joists and rafters. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.

Span tables all span tables. The figures are based on quality materials. Solid timber joist sizes are provided in the bs 8103 3 span tables. View joist rafter tables.

Also available for the android os. 1 enter joist details 1 1 span and joist spacing. 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. Span tables can be used to determine the size of a timber member of a particular strength class required for a given span.

Flat roof joist calculator. Timber floor joists shall be adequate for the spans and loads and be correctly installed. For pitched roofs flat roofs and ceiling joists. Joists rafters simplified maximum span tables for selected visual and mechanical grades of southern pine lumber in sizes 2 4 thru 2 12.

In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. This demo version is fixed at 1m clear span. You can also use the wood beam calculator from the american wood council website to determine maximum rafter and joist lengths. Span calculator for wood joists and rafters also available for the android os.

The tables below give maximum spans for rafters and beams.