Roof Estimating Formulas

This is only important for gable roofs as the calculator uses a specific formula to estimate roof run length of gable.

Roof estimating formulas.

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. 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. The following tools estimate the area of a roof as well as the amount of materials necessary to construct a roof of a given area. However the end result may be well worth it as your roofing material is estimated to last up to 50 longer and will require less maintenance.

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. A 12 in 12 roof can cost up to 50 more than a 4 in 12 roof. 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.