The roof slope factor is written as x 12 where x is the vertical distance you measured from roof to level.
Roof slope factor definition.
Then you ll be able to measure slope from an unfinished attic space under the roof.
Conventional from 4 12 1 in 3 to 9 12 3 in 4.
Roof slope factors valley hip factors.
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.
The slope factor works with metric and imperial measurements.
See low slope roofing.
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.
The slope of a roof often referred to as the pitch is determined by rise over run the roof s vertical rise in inches for every twelve inches of horizontal length the run.
And steep slope roofing which is above 9 12 3 in 4 21 12 7 in 4 and may require extra fasteners.
The headache of using pythagoras and trigonometry can be spared by making use of these charts.
How to determine roof pitch or roof slope.
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.
Using a tape measure make a pencil mark 12 inches from the end of a carpenter s level.
If asphalt shingles are to be installed on a low slope roof special steps are required to avoid short roof life and roof leaks.
So the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally.
Low slope roofs are from 0 to 3 12 in pitch.
You may often hear from a roofing contractor an architect or a framing contractor builder a phrase roof pitch.
The basic ranges of pitch are not uniformly defined but range from flat which are not perfectly flat but sloped to drain water up to 1 2 12 to 2 12 1 in 24 to 1 in 6.
Some sources consider low slope to include 3 12 pitch roofs.
For instance if the measurement was 3 your roof slope factor would be 3 12 and you.
Hip and valley rafters slope factor roofs with hips and valleys have special factors.
Roof area in square metres length in metres width in metres slope factor.
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.
Roof pitch is the most common way in us and canada to describe the roof s basic quality steepness.
A hip or a valley is where two roof slopes intersect forming a peak or a depression.
