Roof Estimating Formulas

Roof pitch roof pitch is the measurement of a roof s vertical rise divided by its horizontal run.

Roof estimating formulas.

Rafter rise run this formula is from the pythagorean theorem. Ranch house using asphalt roof shingles. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. To accurately calculate the area of your roof you must first determine its slope or pitch.

1 roof square 100 square feet. Medium slope roof pitch of 6. It is often compared to slope but is not exactly the same. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs.

Steep slope roof pitch of 12 or 45 degrees. Medium steep slope roof pitch of 9. Use the following formula which also describes a right triangle. L 30 feet h 12 feet 30 12 2 180 square feet.

Here are the equations you may use to solve for the length of the slope and the rafter. Medium low slope roof pitch of 3 or 4. The length l times the height h of a triangle is twice its area a2. Roofing cost can vary widely depending on the size and complexity of your roof type of materials you use as well as your location.

In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches. However if you use premium materials such as metal wood shingles clay tile etc the cost of your roof will be at least 9 500 16 000. To get the slope of your roof based on degrees roof rise or x inches per 12 run use our roof pitch calculator. You can also calculate roof pitch even without using a roof slope calculator.