Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot.
Standard roof pitch angle uk.
Thatch is used occasionally on new dwellings and demands a roof pitch of at least 45 and more likely 50 to allow the rain to flow off quickly and prevent ingress.
Some of the most common roof pitch types are conventional slope type roofs designed with pitch ranging from 4 12 to 9 12.
For instance a 7 12 roof pitch means that the roof rises 7 inches for every 12 horizontal inches.
Express roof pitch as the ratio of the amount of the vertical rise of a roof or rise over the corresponding horizontal distance or run you write the pitch assuming a run of 12 inches thus the ratio would describe how much a roof rises for each foot of the run.
Roof pitch and corresponding angles.
Pitches of less than 2 12 are considered flat roofs even though they may be very slightly angled.
In the usa the range of standard pitches is anywhere between 4 12 and 9 12.
Roof pitch varies depending on culture climate style and available materials.
This measurement is best done on a bare roof because curled up roofing shingles will impair your measurement.
This means if a roof rises 4 in the length of 12 your roof pitch would be 4 12 or 18 43 degrees.
The most commonly used roof pitches fall in a range between 4 12 and 9 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.
Pitches above 9 12 are very highly angled and are designated steep slope roofs.
So if your roof rises 4 inches for every 12 inches of horizontal length then the pitch of your roof is expressed as 4 12.
In the uk the typical house has a pitch between 40 50 although 45 should be avoided.
A ratio is the most common way of expressing roof pitch or roof slope but degrees are also possible.
Roof pitches exceeding the level of 9 12 or approximately 37 degrees are termed steep slope roofs.
The way pitch also known as roof slope is measured is rise over run.
In the united states a run of 12 inches 1 foot is used and pitch is measured as the rise of the roof over 12 inches.
On blue prints architects engineers usually display the pitch of a roof in the format shown on the image where number 4 represents a rise and number 12 represents a length.
A a roof with a 6 rise for every 12 run has a 6 per foot or 6 in 12 pitch.
It is often compared to slope but is not exactly the same.
This steep pitch is also an essential ingredient of cottage style.
Pitches lower than 4 12 have a slight angle and they are defined as low slope roofs.
These are utilized in residential applications.