Roof Estimating Formulas

Recalculate this value into an angle:

Roof estimating formulas.

The formula used to calculate rafter length from roof pitch is, in fact, the same as the one above. Typical price range to install new roof average: 1,500 ÷ 32 = 46.875 sheets.

To get the slope of your roof based on degrees, roof rise or x inches per 12 run, use our roof pitch calculator. Roof type by dividing the roof into sections. All price estimates include the cost of professional roof installation and materials for new or retrofit projects.

Next, you will need to use a roofing materials calculator. Sq x.00694 = sq ft. 3' x 3' = 9sq feet = 1sq yd.

Inches / 12 = ft. For estimating purposes, we also assume that there is a chimney, a couple of dormers, and two layers of old shingles that need to be torn off and removed before a new roof can be installed. The roof pitch can either be low, medium, or high.

For example, if your roof is 1,500 ft 2 then it will take 47 sheets of plywood to sheath it. This gives us a 3d roof area of 1,625 sq.ft. The roof pitch, or how steep it is, is expressed as a ratio.

36 x 36 x 36 = 46,656 cu = 1 cubic yard. A low roof pitch has a ratio of 5:12 or lower, a medium roof pitches 6:12 to 9:12, and a high roof pitches 10:12 to 12:12. Pitch = rise / run = 1.5 / 6 = 25%.