Roof Estimating Multiplier

Roof pitch area multipliers.

Roof estimating multiplier.

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. Next multiply the footprint of the roof by the multiplier below for your roof pitch to find the overall roof area. Find the square root of the result. The pitch of the roof is the rise over a 12 inch run.

This is because a steep sloped roof requires a taller chimney and more lumber for framing. 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. For example a 4 12 pitch roof that is 100 square feet. 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 slope of the roof provides the rise and the run to be plugged into the equation. 100 1 054 105 4ft 2. Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio.

The roof pitch multiplier table is very helpful in giving correct and reliable roof measurements and uses pythagorean theory. 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. A roof pitch of 4 in 12 4 12 has a rise of 4 and a run of 12. 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.

Divide the rise by the run the run is 12. 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.