Roof Estimating Formulas

See the diagram below.

Roof estimating formulas.

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. This is because a steep sloped roof requires a taller chimney and more lumber for framing. A 12 in 12 roof can cost up to 50 more than a 4 in 12 roof. Since it takes 3 bundles of shingles to cover a square plan to purchase 3 bundles for each square.

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. This is only important for gable roofs as the calculator uses a specific formula to estimate roof run length of gable. The roof area is simply 114x18x2 plus 30x18x2 giving 5184 square feet which is perfectly adequate for estimating materials. 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.