If your local building authority has a rafter spacing code you may not space rafters wider than required by code.
Pitched roof rafter spacing.
For pitched roofs flat roofs and ceiling joists.
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.
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.
So the space between rafters can be greater without reducing the maximum span.
The same concept holds true for roof trusses.
If your project had a rafter length of 8 or less a safe and strong method is to use 2x8 framed 16 on center.
Surveyors span tables for designing roof rafters.
Surveyors and structural engineers utilise data from tables below to help calculate the correct size strength and centres of roof timbers for the required spans and loadings.
An essential part of planning a patio roof or gazebo project is determining the number size and spacing of rafters beams and posts according to the loads they will carry.
Typical rafter spacing codes will specify a minimum spacing of 16 inches 19 2 inches or 24 inches.
Rafters must be strong enough to hold the roof sheathing and the shingles.