Roof Estimating Formulas

Add overhangs if you have overhangs on the front back and sides of your house you most likely do take the width of the overhang multiply it by 2 and add to each side.

Roof estimating formulas.

See the diagram below. The house base area is the area of land that the house covers and for more complex shapes can be estimated using the area calculator. A 12 in 12 roof can cost up to 50 more than a 4 in 12 roof. The roof area for a hip end is the same as for a gable end the intersection is equivalent to a hip slightly conservative so there is usually no need to consider triangles when measuring a roof.

To estimate roofing materials start by finding the total square footage of the roof and divide the number by 100 to determine the number of squares in the roof. This is because a steep sloped roof requires a taller chimney and more lumber for framing. This is only important for gable roofs as the calculator uses a specific formula to estimate roof run length of gable. Since it takes 3 bundles of shingles to cover a square plan to purchase 3 bundles for each square.