The framing of a basic gable roof is based on a right angle triangle and the various roof framing components fit the triangle.
Roof frame spacing.
For heavier material such as gage steel the metal roof purlins spacing length could go up to 4 feet.
Most roofs utilize 16 inch spacings for strength and rigidity.
The rafters are usually positioned directly above the wall studs.
Asphalt shingle can be installed on a pitch of 2 over 12 or greater.
Like wall studs and floor joists rafters and trusses are spaced every 16 or 24 inches from center to center.
The figures are based on quality materials.
For the lighter material such as lightweight aluminum the common spacing length is 4 inches of clear gap.
A roof truss is a structural framework usually made from wood that bridges the space between the ceiling of the top level and the roof structure.
Rafter spacing depends on the roofing panel size.
Stick framing combines roof rafters with ceiling joists.
Although the standard spacing of roof trusses may be the same as that of rafters with 24 inch spacing being a common option the design of a truss may allow for the use of a lower grade of lumber than would be required for rafters with comparable spacing and span.
A super basic a frame roof will require anywhere between 4 and 8 depending on the size of the rafters with plumb cuts necessary for each angle in the brace.
The pitch of the roof determines the roofing material you can use.
And the line length measurement from the roof peak to the building wall is the hypotenuse.
In areas with mild climates patio roofs are generally designed for loads of 30 psf pounds per square foot.
These are typically spaced at certain intervals to provide the necessary support for the roof.
The run or half the building span is the base of the triangle.
There are special shingles available for 2 12 but you re better off using other materials.
Designing roof trusses for proper placement on post frame buildings.
The rise or height of the roof at its peak is the altitude of the triangle.
The tables below give maximum spans for rafters and beams.
The typical spacing standards for residential and commercial buildings are about 1 to 2 foot.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
It must meet the local codes for thickness at least 3 8 which is also based on the rafter or truss spacing.
Very simple trusses work on a principle of thirds.
Metal roofs and pole buildings.
