Roof Estimating Formulas

Since it takes 3 bundles of shingles to cover a square plan to purchase 3 bundles for each square.

Roof estimating formulas.

The roof area is simply 114x18x2 plus 30x18x2 giving 5184 square feet which is perfectly adequate for estimating materials. A 12 in 12 roof can cost up to 50 more than a 4 in 12 roof. See the diagram below. This is only important for gable roofs as the calculator uses a specific formula to estimate roof run length of gable.

This is because a steep sloped roof requires a taller chimney and more lumber for framing. 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. 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. 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.