IDEAL ROOF PITCHES
simple RULE Roof Framing: Three Pitches in Common Use
Fig. 40 shows the three pitches in common use.
“The pitch at e is called the square pitch, the slant of one side of the roof being at right angles to the slant of the other side, the pitch of the roof being 45 degrees. [12:12 pitch]
The pitch at d is 2/3 pitch, the length of the rafters being 2/3 of the width of the building. [12:9 pitch]
The pitch at c is called 1/2 pitch, the rise being 1/2 of the width of the building…” [12:6 pitch]