Framing & StructuralQuestion 400 of 700
A common rafter has a horizontal run of 10 feet and a rise of 5 feet. What is the roof slope expressed as unit rise per 12 units of run?
a.3:12
b.4:12
c.6:12
d.12:12
Explanation
Slope in rise-per-12 equals (rise / run) x 12 = (5 / 10) x 12 = 6, so the slope is 6:12. 3:12 and 4:12 are shallower than the actual ratio, and 12:12 would require the rise to equal the run.
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