Roof Area Pitch Factor

A roof pitch multiplier also known as a roof pitch factor is a number that when multiplied by the area covered by a sloped roof gives the actual area of the roof.

Roof area pitch factor.

The formula for the roof pitch multiplier comes from the formula for a right triangle and more specifically the pythagorean theorem. Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. 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. Roof pitch affects the actual area of the roof.

If you do not wish to climb on the roof to calculate roof pitch then use a ladder. The procedure to follow is the same. Roof pitch is a determining factor for cost of the roof as well as the roof area and the type of materials used. It is sometimes called the roof pitch multiplier.

What is the roof pitch factor. It affects walkability as well as drainage and roofs in areas of high rain or snowfall tend to have steeper pitches. A roof pitch multiplier also called a roof pitch factor is a number that is multiplied by the area covered by a sloped roof to produce the area of the actual surface of the roof. The roof pitch conversion factor is a number that when multiplied by the area covered by the roof gives an estimate the total surface area of the sloped roof itself.

In our example the roof pitch was calculated as 9 12 which has a factor of 1 25 in the table. This nominal square footage amount is then multiplied by a factor associated with the roof s pitch. Add 1 then take the square root. For example if you measure 4 inches the pitch of your roof is 4 12.

How roof area is calculated. The maths behind this number is that it is the square root of rise run 2 1. So keeping with our roof pitch of 4 this gives us 1 9. From the roof pitch factor table note down the roof pitch conversion factor corresponding to the roof pitch calculated.

If the area is 10 000 squares then roof pitch would be 12 500 10 000x1 25. This will give you the rise over run or pitch. Simply locate a roof rafter board place the end of the level against the bottom edge and measure from the 12 inch mark vertically to the bottom edge of the rafter. The roof pitch can also be determined by staying.

You can calculate roof pitch from the rafter tail bottom or at a barge rafter at the gable end on the roof over hangs. Feet the area of a hip roof equals the area of a gable roof with the same dimensions. Then multiply the square footage with the roof pitch factor to get the total area of the roof.