Patio Cover Roof Pitch
The patio cover has a pitch that allows rainwater or melting snow to flow down to the built-in gutter system and downspouts.
What is the pitch for a patio cover?
The pitch for a patio cover, also known as its slope, is measured in a ratio of inches per foot. For Alumawood patio covers, the minimum slope is 1/4" per foot, while the maximum slope is 1" per foot.
It is crucial to note that the maximum slope ensures proper contact between the roof panels, hanger, and beam.
On the other hand, Pergola Lattice covers do not have a specific minimum pitch requirement and can be flat if desired. However, the maximum slope for these covers is also 1" per foot. To calculate the overall rise or fall of your roof, you can simply multiply the roof slope by the distance from your home to the center of the beamline.
Below is a list of sizes with the minimum and maximum slopes, along with a detailed example of a 10' projection for further guidance.
DIY Patio Cover Calculator – Roof Pitch & Post Height Drop
Enter your roof pitch and projection to instantly see the roof drop at the post line. This quick calculator helps you measure how far your patio cover will slope, so you know the exact post height and where to attach at the house—no math required.
Patio Cover Roof Pitch FAQ
How do I measure roof pitch for a patio cover?
Roof pitch is measured in inches of drop per foot of projection. For example, a 1/4" pitch means the roof drops 1/4 inch for every foot out from the house.
What does roof drop mean?
Roof drop is the total vertical distance your patio cover lowers from the house attachment point down to the post line. This calculator shows the roof drop in inches.
Why does post setback matter?
The post setback is how far back your posts are from the front edge of the cover. It changes where the drop is measured, so you know the true post height you need.
How accurate is this calculator?
The calculator uses standard roof pitch math. It gives you an exact drop in inches based on your inputs. Always double-check with your local building codes before cutting posts.
Total roof fall per projection:
6' Projection = 1 1/4" Min. to 5" Max.
7' Projection = 1 1/2" Min. to 6" Max.
8' Projection = 1 3/4" Min. to 7" Max.
9' Projection = 2" Min. to 8" Max.
10' Projection = 2 1/4" Min. to 9" Max.
11' Projection = 2 1/2" Min. to 10" Max.
12' Projection = 2 3/4" Min. to 11" Max.
13' Projection = 3" Min. to 12" Max.
14' Projection = 3 1/4" Min. to 13" Max.
15' Projection = 3 1/2" Min. to 14" Max.
16' Projection = 3 3/4" Min. to 15" Max.
17' Projection = 4" Min. to 16" Max.
18' Projection = 4 1/4" Min. to 17" Max.
19' Projection = 4 1/2" Min. to 18" Max.
20' Projection = 4 3/4" Min. to 19" Max.
Note: Based on drop to beam, beam line is typically set back 1' from the end of the projection.
Traditional patio cover numbers will vary as many applications do not use a setback beam.
Here is an example of calculating the roof pitch.
Based on a 10' Projection
You need to determine where your attachment location and then measure down to the ground, which will give you a close measurement.
The roof will rise from the roof's pitch from the post location.
1/4" pitch = Approx. 2 1/4" gain in height from post to hanger.
1/2" pitch = Approx. 4 1/2" gain in height from post to hanger.
1" pitch = Approx. 9" gain in height from post to hanger.
Loss of Projection Distance with Roof Pitch (how much projection is lost by roof pitch)
The average roof pitch is .25" per foot, with a maximum of 1" per foot. You're not losing much projection out with the pitch.
1/4" pitch = 1/32" loss of projection
1/2" pitch = 1/8" loss of projection
1" pitch = 7/16" loss of projection