Flat Roof Joist Span Calculator

This demo version is fixed at 1m clear span.

Flat roof joist span calculator.

Timber to be covered these span tables do not apply to timber which is fully exposed to the elements. Usually 400 450 or 600mm but any value can be used up to 610mm max. For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements. 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.

To size joists and rafters use the maximum span tables for southern yellow pine. More roof calculators roof truss calculator how to cut rafters. 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. 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. 1 enter joist details 1 1 span and joist spacing. 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. The full version allows any size.

This rafter span calculator is species specific for douglas fir hemlock etc. 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. 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. This is the distance between joist centres.

The truss is a framework consisting of rafters posts and struts which supports your roof. Flat roof joist calculator. 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. 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.

This is based upon the span of the rafter horizontal span not total rafter length live and dead loads.