Roof Joist Angle Span

While pitch and slope are used interchangeably they are not the same span also known as gable width this is based on the total footprint of the house and refers to the distance between two exterior walls.

Roof joist angle span.

Also available for the android os. The table states that 2 x 6 rafters spaced 16 inches on center o c can span a maximum distance of 13 feet 5 inches. In snowy areas your roof should be at least 10 12 40 to allow snow to shed while the safest roof pitch in very windy areas is between 4 12 6 12 18 5 26 5. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length.

Another option are 2 x 8 rafters spaced 24 inches o c. For example you can span a 1 grade no knots southern yellow pine a greater distance than a 2 grade with knots southern yellow pine. Includes result for hip valley factor slope factor and the roof slope in degrees. The lengths and sizes of joists vary depending on the species and quality of the lumber used.

Lh and dlh series joists are for longer span conditions and are capable of supporting larger loads. Roof angle 1 1 5 2 2 5 3 3 5 4 4 5 5 5 5 6 6 5 7 7 5 8 8 5 9 9 5 10 10 5 11 11 5 12 12 5 13 13 5 14 14 15 5 15 5 16 16 5 17. Kcs joists are a version of the k series joists but designed for a constant shear and moment which allows for greater flexibility for locating extra loads such as those from rooftop units. Span calculator for wood joists and rafters also available for the android os.

Rafter and joist span faq. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. To size joists and rafters use the maximum span tables for southern yellow pine. This is based upon the span of the rafter horizontal span not total rafter length live and dead loads.

This rafter span calculator is species specific for douglas fir hemlock etc. These joists are typically used in roof structures. In making your choice consider how you will insulate your insulate your roof. For example in the rafter span table below the highlighted cell in the 40 live load table indicates that 2 x 8 southern yellow pine joists that have a grade of 2 that are spaced 24 apart can have a maximum span of 10 feet 3 inches 10 3 if designing for a live load of 40 lbs ft 2.