Roof Area Factor

For example suppose you have a 4 12 pitch roof and the width of the house is 28 feet.

Roof area factor.

Thus a moderate 6 in 12 roof pitch means that the roof rises 6 inches vertically for every 12 horizontal inches it runs. A roof s pitch is determined by how much it rises vertically for every foot it runs horizontally. Multiply the result by the factor and this is the length of the roof from base to ridge. In our example the roof pitch was calculated as 9 12 which has a factor of 1 25 in the table.

Roof area in square metres length in metres width in metres slope factor roof area in square feet length in feet width in feet slope factor. When outfitting your residential or commercial structure with products from everlast roofing it s important to know the incline or pitch of your roof. Looking at the chart the factor is 1 0541. Download the slope chart pdf.

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 last step is to come off the ladder and simply multiply the factor determined in the step above with the number of total squares of the area. Depending whether the roof area is measured horizontally possibly from a drawing or photograph a correction factor is necessary to determine the actual area of the roof. You can consult the following chart to discover the slope factor and hip valley factor.

In construction the slope factor can be used to easily calculate the area of a roof. Now you re ready to price out the materials. Then multiply the square footage with the roof pitch factor to get the total area of the roof. That is if your tape reads 7 then add 1 that will give you 8 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. To accurately calculate the area of your roof you must first determine its slope or pitch. Dividing the house width by two equals 14 feet. The answer is the area of your roof.

Multiply the square footage you calculated in step 1 by the pitch factor you determined in step 3. Given pitch and a horizontal area measurement multiply the horizontal area by a correction factor corresponding to pitch provided in the table below to determine the actual area of the roof to be used in the roofing material calculator. Take your area result and multiply it by the pitch multiplier or slope correction factor found in the table above to arrive at the roof s surface area. If the area is 10 000 squares then roof pitch would be 12 500 10 000x1 25.

The slope factor works with metric and imperial measurements.