It is always better to have a large rafter rather than be concerned with a sagging roof.
Rafter spacing for metal roofing.
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.
Rafter spacing for metal roof purlin hangers clips are available if you would rather the purlin be on the same level as the rafter rather than on top of the rafter.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
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.
Structures such as sheds or barns can be frames with rafters every 24 again make sure to consult local codes.
A metal roof must also allow for some overlap on each side of the panels which will reduce the effective width of the panel.
The width of metal panels will determine the rafter spacing.
Other relevant factors include the type of wood being used for the rafters the size of the rafters and the load that the rafters need to support.
Rise and run means that a 6 12 pitch roof has 6 of rise vertical for each foot of run horizontal.
The spacing between rafters in a given building is part of the engineering calculations that determine the required structure of the roof.
The wider the roofing panels the greater spacing distance you should put.
There is a chance of damaging roofing sheets if you are failed to do so.
Wider panels allow for greater spacing between rafters.
Rafter spacing is based on the width of the metal roofing panels.
For heavy roofs or in areas with substantial snowfall or winds call your local building department for code requirements.