The following table shows how the same common roof slopes can be expressed using rise in run ratios degrees and percentages.
Roof slope factgore.
Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof.
See below after the table for directions on how to convert any roof slope from one form to another even roof slopes not shown in the table.
The roof slope factor is written as x 12 where x is the vertical distance you measured from roof to level.
Roof pitch calculator roof slope calculator the roof pitch calculator is a convenient online tool you can use to quickly assess the pitch of your roof to determine the length of rafters you need.
You could calculate the slope factor for every single roof pitch but as a public service many roofing companies provide slope factor charts.
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.
In construction the slope factor can be used to easily calculate the area of a roof.
For instance if the measurement was 3 your roof slope factor would be 3 12 and you.
The roof slope factor chart also consists of conversion factors to determine the slope of the roof.
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.
Also see our page quick reference.
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.
After finding out your roof pitch angles you can use the calculator to perform the calculations for you instead of doing them manually.
The slope factor works with metric and imperial measurements.
For instance the ever last roofing company distributes a chart to the general public.
For example if you measure 4 inches the pitch of your roof is 4 12.
It s just a little math.
Degrees to roof pitch rise in run to see a table.
The combination of two numbers are used to display or show the roof pitch.
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.
The headache of using pythagoras and trigonometry can be spared by making use of these charts.
The maths behind this number is that it is the square root of rise run 2 1.
