Rafter and roof joist spacing is only one part of a complex roof design that works together to form a structure that meets building codes and can hold up the weight of the roof and roof load.
How far apart are roof joists on 10x10 lean to.
Measure from the ends.
If the roof is not completely square you can decrease the space between joists but never increase the space.
Frame the top side wall of the lean to roof with 2x4 lumber.
But they do tend to space rafters in one of several industry standard increments.
Then use the circular saw to cut a 1 by 3 5 inches 2 5 cm 8 9 cm notch 10 25 inches 26 0 cm from the top of each rafter.
A roof joist is always spaced no more than 16 inches apart from another roof joist.
Builders aren t bound by standard rafter spacing measurements.
In other words you would space a roof joist 15 inches apart from another roof joist but never 17 inches apart.
Cut the joists to the intended width of your shed.