Roof Estimating Multiplier

Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio.

Roof estimating multiplier.

This is because a steep sloped roof requires a taller chimney and more lumber for framing. Just multiply the roof width by roof length and then the result should be multiplied by the use of the pitch multiplier. Divide the rise by the run the run is 12. The slope of the roof provides the rise and the run to be plugged into the equation.

Assuming this is a hip roof we multiply this by 1 1 which gives us roughly 18 squares or 1 800 square feet of the roof surface. 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. Next multiply the footprint of the roof by the multiplier below for your roof pitch to find the overall roof area. The pitch of the roof is the rise over a 12 inch run.

For example a 4 12 pitch roof that is 100 square feet. Roof pitch area multipliers. 100 1 054 105 4ft 2. Accurate roof calculations are achieved using this table and all you need to do is measure the roof width and length and then you are ready to do a roof pitch measurement.

A roof pitch of 4 in 12 4 12 has a rise of 4 and a run of 12. A 12 in 12 roof can cost up to 50 more than a 4 in 12 roof. Find the square root of the result. This gives us a 3d roof area of 1 625 sq ft.

Use our roof pitch calculator to find the pitch of your roof. The roof pitch multiplier table is very helpful in giving correct and reliable roof measurements and uses pythagorean theory.