The spans in this table are based on a maximum supported rafter span of 16 feet where the supported span is the total horizontal distance spanned by the roof rafters divided in half not the diagonal distance or the length of the rafter.
Roof hip spans.
So this table could accommodate a house with a total rafter span or house width of 32 feet.
Select the following information by using the drop downs to enter values in feet and inches.
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.
Roof load width rlw and floor load width flw can be determined from as1684 or from the images below.
Hip roofs are more stable than gable roofs and more resistant to strong winds and hurricane.
Span for the main rafters measure from outside of wall to outside of wall.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
Live load is weight of furniture wind snow and more.
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.
2 are indicated below.
Required size for a given span.
Douglas fir maximum horizontal roof rafter span for lumber grade selected structural and no.
1 psf lb f ft 2 47 88 n m 2.
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.
1 ft 0 3048 m.
They must must be on the same level.
Dead load weight of structure and fixed loads 15 lbs ft 2.
Spacing should be interpreted as the centre to centre distance between adjacent parallel members.
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.
Wood beam calculator american wood council website rafter and joist span faq.
The 1 grade.
The hip roof framing calculator returns the value of the main rafter the side rafter the length of the hip the height of the knee wall and the lengths of the jack rafters.
Span calculator for wood joists and rafters also available for the android os.