BidMagic Construction Estimating Software-- Roof Slopes

Estimating Roofing Slopes

NOTE-- We retired BidMagic construction estimating software back in 2001. It has been replaced by Goldenseal construction estimating software.

We still include this BidMagic estimating software manual as a convenience for users of our older program. Many features are similar, in Goldenseal estimating.

Roof Slopes

The BidMagic construction estimating software uses the roof slope to calculate roofing area and other roof measurements.

For shed, gable and hip roofs, enter the slope of the main roof. For mansard and gambrel roofs, enter slopes for both the upper and lower portions of the roof. To compute the roof slope for these roofs, measure one foot horizontally, and enter the number of inches that the roof rises.

What is commonly known as a 4/12 pitch has 4 inches of rise per foot of horizontal run, so you'll enter a 4 for its slope. A 12/12 pitch (shown at right) has 12 inches of rise per foot of horizontal run, so you'll enter a 12 for its slope.

For arch and dome roofs, enter the slope in degrees for both the flattest and steepest portion of the roof. Enter 90 for a vertical pitch, 0 for a horizontal (flat) pitch, and an intermediate value for a sloping pitch.

Use the table in the printed manual to convert between inches per foot, degrees, and fractional 'pitch' for some common roof slopes.