how do i determine the length of my roof for shingles?
 Determine the pitch of the roof. The pitch is how steep the roof is. Pitch is calculated by the roof's rise over its run. Measure from the edge of the roof over 12 inches (12 is the run) and see how many inches up the roof line is (this is the rise). Get a slope multiplier from the chart below.. Determine the pitch of the roof. 