Flat Roof Joist Span Calculator

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.

Flat roof joist span calculator.

1 enter joist details 1 1 span and joist spacing. To size joists and rafters use the maximum span tables for southern yellow pine. 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. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.

This is the distance between joist centres. While every effort has been made to insure the accuracy of the information presented and special effort has been made to assure that the information reflects the state of the art neither the west coast lumber inspection bureau the american wood council nor its members assume any responsibility for any particular design prepared from this online span calculator. These span tables apply only to flat roof and roof with a slope of up to 10 degrees. 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. The truss is a framework consisting of rafters posts and struts which supports your roof. 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. Also available for the android os.

This rafter span calculator is species specific for douglas fir hemlock etc. Span calculator for wood joists and rafters also available for the android os. Usually 400 450 or 600mm but any value can be used up to 610mm max. Flat roof joist calculator.

More roof calculators roof truss calculator how to cut rafters. Use this table to determine the maximum lengths of floor joists based on species of lumber joist spacing and joist size. Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. The full version allows any size.

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.