A 4 12 is a roof slope that rises by 4 inches for every 12 inches across.
Roof slopes with angles.
You can assess this in two ways either as the roof pitch angles which the rafters make with the horizontal or the proportion between the run and the rise of the roof.
The 45 degree roofs seen on a frame houses are 12 in 12 but roofs can be even steeper consider the mansard roofs introduced by french second empire architects in the middle of the 1800s.
First convert the pitch to a slope.
Roof pitch refers to the slope which the rafter creates.
Two most common methods 4 12 or 4 12 are used for marking the pitch of a roof.
The a frame style roof shown just above located on highway 61 just south of hovland minnesota is built at a 75 angle and is considered a very steep roof.
Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs.
Mansard roofs with nearly vertical faces can boast a pitch of 20 in 12.
This is useful because sometime you may need to cut a bevel with your circular saw that is not calibrated using roof pitch style this setting on circular saws is calibrated in degrees.
The combination of two numbers are used to display or show the roof pitch.
Angle the angle of a roof is the same as the roof s slope except instead of being represented as x 12 it is represented in degrees.
Often you express roof pitch as the ratio between the rise and the run in the form of x 12.
The picture below shows the pitch of a 7 12 roof slope meaning that for 12 of horizontal measurement roof run the vertical measurement roof rise is 7.
The following table shows the roof pitch rise in run equivalents for all roof slopes in degrees from 1 to 72.
Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled.
This forms an angle of 18 5 between the horizontal section and the roof and creates a gentle incline that is seen as a midpoint between a low pitch and medium pitch roof.
The table below describes different roof slopes giving roor slope in rise run in inches and re expressing the same slopes as angle grade walk ability and roof type or class.
Pitched roofs begin with with slopes greater than 3 in 12.
This is our pitch calculator which will convert pitch to angle or angle to pitch for half degree roof slope calculations.
The most commonly used roof pitches fall in a range between 4 12 and 9 12.
Enter any pitch or fraction of pitch to find angle.
To find the angle of a roof in degrees convert the pitch to a slope then convert to degrees by finding the arc tangent of the slope.
Other than the 45 roof slope which is 12 in 12 none of the standard roof pitches 5 in 12 6 in 12 etc are equal to a whole degree.
To do this simply convert the rise and run as a fraction to a decimal form eg.
