Sheathing should be a minimum of 19 32 inch thick.
Roof frame span.
The tables below give maximum spans for rafters and beams.
As a general rule roofs that have a high human occupancy rate should be framed with rafters every 16 structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.
1 used under dry conditions with lumber moisture co ntent less than 16 percent at time of installation.
Span calculator for wood joists and rafters also available for the android os.
So this table could accommodate a house with a total rafter span or house width of 32 feet.
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.
The typical thickness range for sheathing is 3 8 to 3 4 inch.
Never attach roof sheathing with staples.
Span is the horizontal distance between the outside top plates or the base of two abutting right triangles.
Rafter and joist span faq.
Designing with roof rafter span tables roof framing learn how to frame a load power beam anthony forest s cotimber steel framing manual single span ridge beamglulam ridge beam span table elcho.
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.
The lengths and sizes of joists vary depending on the species and quality of the lumber used.
Refer to the figure as you study the terms discussed in the next paragraphs.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.
Maximum rafter spans for a patio roof.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
Unit of run is a fixed unit of measure always 12 inches for the common rafter.
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 areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
Features associated with basic roof framing terms are shown in figure 2 2.
Roof sheathing comes in grid marked 4 by 8 foot sheets and should be installed perpendicular to the frame.
8d ring shank nails should be used instead.
Also available for the android os.
