Q: What’s the easiest way to measure the slope of a roof?
A: A carpenter’s square (L-shaped) is probably the simplest tool to measure roof slope, which is also referred to as the roof’s “pitch”. Hold the square against the sloping roofline with the short arm pointing downward and the horizontal long arm pointing to the opposite side of the roof. Position the long arm so it intersects the roof at the 12-inch mark. With the square held level, measure down from the vertical arm to the point of intersection. Roof slope is indicated by the number of inches the roof rises for each 12 inches of horizontal run. If the vertical arm intersects the roof at the 4-inch mark, it has a 4-in-12 slope.