CHOOSING THE RIGHT BIN FOR YOUR ROOFING JOB! Calculating for the number of squares. 1st Steps calculate the number of squares (WIDTH OF ROOF x LENGTH OF ROOF = SQUARE FOOTAGE OF ROOF). A roofing square is equal to 100 square feet. There are 3 bundles of shingles in each square. Then take the square footage of your roof and divide that by 100 to get your number of squares. (WxL=SQ FT) (SQFT/100= #OF SQUARES) Calculating the weight of roofing materials in tons to determine bin size . (2,000lbs= 1 ton) Take pounds per square and multiply that by the number of squares, and that will equal your total weight in pounds, then divide total weight in pounds by 2,000 to calculate your weight in tons. (LBS PER SQUARE x #OF SQUARES = TOTAL WEIGHT IN POUNDS) (TOTAL WEIGHT IN POUNDS/2,000 = WEIGHT IN TONS) Standard three-tab shingling is 235 pounds per square. Dimensional/Architectural shingling is 350 pounds per square (this is an average dimensional shingles can vary in wei...