Roof Slope Factor Definition

The slope factor works with metric and imperial measurements.

Roof slope factor definition.

Conventional from 4 12 1 in 3 to 9 12 3 in 4. Using a tape measure make a pencil mark 12 inches from the end of a carpenter s level. And steep slope roofing which is above 9 12 3 in 4 21 12 7 in 4 and may require extra fasteners. For instance if the measurement was 3 your roof slope factor would be 3 12 and you.

If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks. Roof pitch is the most common way in us and canada to describe the roof s basic quality steepness. So a roof with four inches of rise every 12 inches horizontally run would have a slope of 4 12 sometimes displayed as 4 12. A 10 slope roof should not be confused with a 10 pitch roof as a 10 slope roof means that the roof rises by ten inches for every foot of run.

You may often hear from a roofing contractor an architect or a framing contractor builder a phrase roof pitch. The roof slope factor chart also consists of conversion factors to determine the slope of the roof. Charts are helpful because the factors for hips and valleys are listed which is useful for cutting rafters on the hip or valley. In construction the slope factor can be used to easily calculate the area of a roof.

Low slope roofing which requires special materials and techniques to avoid leaks and ranges from 1 12 2 12 to 4 12 1 in 3. Roof area in square metres length in metres width in metres slope factor. Roof slope factors valley hip factors. The roof slope factor is written as x 12 where x is the vertical distance you measured from roof to level.

Low slope roofs are from 0 to 3 12 in pitch. See low slope roofing. Some sources consider low slope to include 3 12 pitch roofs. A hip or a valley is where two roof slopes intersect forming a peak or a depression.

So the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally. Then you ll be able to measure slope from an unfinished attic space under the roof. To obtain an accurate roof pitch measurement properly measure the rise and run. If a roof increases in height by four inches for every foot of horizontal run it is considered to have a 4 in 12 pitch or just a 4 pitch talk in terms of pitches and you will always be understood in the roofing universe.

The headache of using pythagoras and trigonometry can be spared by making use of these charts. How to determine roof pitch or roof slope.