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.

Rafter and joist span faq. 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. To size joists and rafters use the maximum span tables for southern yellow pine. More roof calculators roof truss calculator how to cut rafters.

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. This is based upon the span of the rafter horizontal span not total rafter length live and dead loads. Pitch this is the incline of the roof expressed as a fraction. 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.

In making your choice consider how you will insulate your insulate your roof. This rafter span calculator is species specific for douglas fir hemlock etc. For a gothic style the rafters must equal the span 60 while an elizabethan style requires the rafters to be longer than the span. Also available for the android os.

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. If you add an eaves overhang dimension then the amount the rafter sticks passed the wall will be added to the rafter length. Calculate the length of a rafter from the roof slope ratio of inches per foot and a building width measurement. Includes result for hip valley factor slope factor and the roof slope in degrees.

Another option are 2 x 8 rafters spaced 24 inches o c. Span calculator for wood joists and rafters also available for the android os. The lengths and sizes of joists vary depending on the species and quality of the lumber used. These joists are typically used in roof structures.