Flat Roof Joist Span Calculator

For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.

Flat roof joist span calculator. Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Also available for the android os. Usually 400 450 or 600mm but any value can be used up to 610mm max. 1 enter joist details 1 1 span and joist spacing.

The important point to keep in mind when you use your truss calculator is that every truss calculation is completely unique and is based on the size of your roof and its specific dimensions. This demo version is fixed at 1m clear span. This is based upon the span of the rafter horizontal span not total rafter length live and dead loads. More roof calculators roof truss calculator how to cut rafters.

Maximum rafter spans for a patio roof in areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot. The full version allows any size. Span calculator for wood joists and rafters also available for the android os. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements.

These span tables apply only to flat roof and roof with a slope of up to 10 degrees. 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. The truss is a framework consisting of rafters posts and struts which supports your roof. To size joists and rafters use the maximum span tables for southern yellow pine.

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. 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. 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. Span tables for flat roof joists to bs 5268 7 2 imposed loads of 0 75 kn m for maintenance and snow load are applicable where there is no permanent access no fixed ladder or staircase and most areas where the altitude does not exceed 100 metres refer to bs 6399 3.

This rafter span calculator is species specific for douglas fir hemlock etc.