Pitch Roof Slope Angle

Rise run rise run slope.

Pitch roof slope angle.

You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof. On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length. A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible. The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.

Often you express roof pitch as the ratio between the rise and the run in the form of x 12. To do this simply convert the rise and run as a fraction to a decimal form eg. This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement. To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope.

Roof pitch is a term describing how steep or flat your roof slope is. You can also divide the rise over run multiply by 100 and get a percentage. Roof pitch refers to the slope which the rafter creates. Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof.

First convert the pitch to a slope. Thus a 4 12 pitch would be a 33 slope. The minimum roof pitch for shedding snow is around 30 or a 6 12 or 7 12 slope although this is not a definite as the material of your roof the direction of the snow and wind are some factors that can affect whether or not snow will slide as roofs of as little as 10 have been reported to shed snow.