Here is a real simple no cost way. Use Google Earth, measure areas to be cleaned. then use the following conversion for pitch of roof. this will give you the total squares.
Slope Factors: When scaling a roof size from a drawing, multiply the roof area X by the slope factor = total area
2/12 Roof Area x 1.0147 = total area without waist
3/12 Roof Area x 1.031 = total area without waist
4/12 Roof Area x 1.054 = total area without waist
5/12 Roof Area x 1.083 = total area without waist
6/12 Roof Area x 1.118 = total area without waist
7/12 Roof Area x 1.158 = total area without waist
8/12 Roof Area x 1.202 = total area without waist
9/12 Roof Area x 1.250 = total area without waist
10/12 Roof Area x 1.302 = total area without waist
11/12 Roof Area x 1.357 = total area without waist
12/12 Roof Area x 1.413 = total area without waist
