Roof Estimating Multiplier

Roof pitch area multipliers.

Roof estimating multiplier.

A roof pitch of 4 in 12 4 12 has a rise of 4 and a run of 12. Use our roof pitch calculator to find the pitch of your roof. 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 slope of the roof provides the rise and the run to be plugged into the equation. This gives us a 3d roof area of 1 625 sq ft. For example a 4 12 pitch roof that is 100 square feet. The roof pitch multiplier table is very helpful in giving correct and reliable roof measurements and uses pythagorean theory.

Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio. The pitch of the roof is the rise over a 12 inch run. 100 1 054 105 4ft 2. This is because a steep sloped roof requires a taller chimney and more lumber for framing.

Divide the rise by the run the run is 12. Although there s isn t any standard pitch of a roof used on all kinds of sloped roofs you can determine the range of pitches by using a roof angle calculator and by considering factors like the local climate and roofing materials. Just multiply the roof width by roof length and then the result should be multiplied by the use of the pitch multiplier. A 12 in 12 roof can cost up to 50 more than a 4 in 12 roof.

For roof slopes expressed as x in 12 rise in run the roof pitch multiplier is determined by finding the square root of rise run 1. 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.