Roof Area Calculators: For each of the roof types pictured below, L
= Horizontal Length, W = Horizontal Width, and H = Vertical Height, all entered in feet. Slope in inches per foot
may substituted for H.
Hip roofs can present a problem for height measurement, and the slope method may be substituted
in place of height measurement. Since modern architecture has allowed the incidence of mixed slopes in a single
structure, the calculator allows for entry of differing slopes for intersecting roofs.
For many roofs, dimensions can be taken from the ground or from a ladder. Be sure that your measurements
include any overhang at the eaves. Height can often be measured at the end wall at the center of a gable.
Complex roofs may have numerous repeats of these shapes - perform a separate calculation for each section,
then add the results together (on paper) to obtain total roof area. A "salt box" roof with
unequal sides may be calculated as two separate shed roof shapes. An "A-Frame" roof is
simply a gable with high slope.