4/12 Roof Pitch
A 4/12 roof pitch can also be expressed as 4 over 12 and when you're talking to a roofer, this is the most common way you'll hear it explained because it's easy to say in conversation.
Another way to express a 4/12 pitch is "4 and 12."
In this pitch, the four is your roof's rise and the twelve is the roof's run. The roof's incline increases four feet for every 12 feet of horizontal measurement.
What angle is a 4 over 12 pitch?
Roofs with a pitch of 4/12 are approximately 18.4 degrees, depending on how exact you'd like to be in your measurement.
Check out our roof angle chart for more examples of the exact angles (expressed in degrees) of common roof pitches.
Visual Examples
Above is an roof replacement in Fitchburg, Massachusetts we completed this year. The entire roof is a 4/12 pitch and you'll see in the picture that it isn't very steep. When re-roofing a home with a 4 and 12 pitch, you don't have to be as careful of your footing compared to when you're roofing a steeper pitch like the roof below.
Part of the roof on this roofing project we completed in Roslindale, MA was a 4 over 12 dormer. You can see it marked by the blue arrow on the right that says 4/12.
Compared to the first example on this page (the gray roof), you can see how much steeper the entire roof is here. That's because the majority of the home had a 12/12 pitch, which made it a steep slope (and a much more dangerous job for our crew).
10/12 Roof Pitch
A 10/12 roof pitch can also be expressed as 10 over 12 and when you're talking to a roofer, this is the most common way you'll hear it explained because it's easy to say in conversation.
A 10/12 roof pitch is steeper than average, so it is a little harder and more expensive to install. A benefit of this pitch is that it will shed water effectively without requiring larger gutters.
Another way to express a 10/12 pitch is "10 and 12."
In this pitch, the 10 represents your roof's rise and 12 represents the roof's run.
The roof's incline increases ten feet for every 12 feet of horizontal measurement.
What angle is a 10 over 12 pitch?
Roofs with a pitch of 10/12 are approximately 39.81 degrees, depending on how exact you'd like to be in your measurement.
Check out our roof angle chart for more examples of the exact angles (expressed in degrees) of common roof pitches.
Visual Examples
Pictured above is a Boston roof replacement we completed last Winter on a one story home. The entire roof is a 10 over 12 pitch, which is one of the steeper residential pitches to re-roof. You need to be careful when walking a roof of this steepness.