The calculated area is only an estimation. In cases where a roof has a complex shape, such as in the image to the right, measuring the dimensions and areas of each part of the roof to calculate total area will result in a more accurate measurement of area. The calculator cannot account for complex shapes based on a measurement of square footage alone. The Area Calculator can be used to calculate the area of a variety of simple shapes that together can comprise the area of the roof. Using the aggregate area of these simple shapes can yield a more accurate roof area to be used with the Roofing Material Calculator.
The most common roofing materials used in the United States include shingles, membrane roofing, and ceramic tile, all of which have different life spans. Shingle roofs typically have a life span of 15-30 years, while membrane roofs usually last 5-15 years. Although ceramic tile roofs are expensive, they can have a life span of over 100 years.
How to calculate the roof area
- Begin with calculating the area of your house in a plane parallel to the ground.
- Determine the roof pitch of your house.
- Convert roof pitch using:
pitch(%) = x / 12 * 100%pitch(deg) = arctan [pitch(%)]
- Calculate total area using:
roof area = base area / cos[pitch(deg)]
Roofing Tips: Roof Slope & Style
There are two main categories of roofing: sloped and flat. A flat roof has a slope of 2 in 12 or less. The run always remains constant at 12 inches. A low slope roof is anywhere from 2 in 12 to 4 in 12. Conventional slope roof range between 4 in 12 and 8 in 12. Anything more than 9 in 12 is considered steep. Steeper-sloped roofs are considered more aesthetically pleasing and last longer. These benefits do not come cheaply though. A 12 in 12 roof can cost up to 50% more than a 4 in 12 roof.
Roof styles or types are usually predesigned by the builder of your home. A gabled roof looks like two sides of a triangle. A shed roof is slanted one way. Gambrel roofs resemble barn roofs. Mansard roofs have a flat top with sloped sides that hang over the home.
What is a Roofing Square?
Roof surfaces are measured in “squares”. A roofing square is equal to 100 square feet of the roof.
To determine the number of squares on the gable roof example, divide its total of 24,000 square feet by 100 (24,000 ÷ 100 = 240).
A roofing contractor might even charge you more labor fees for a roof replacement job by claiming that your roof is larger than it is or that it has a more complex layout than a standard roof. With the data from your Satellite Roof Report, you can cut out unethical charges and miscalculations in the early stages of your project. The Roofing Calculator keeps your roof replacement project transparent and free from costly surprises.