What’s the difference between roof slope and roof pitch?

Roof slope and pitch are often used interchangeably, but they are technically different. Slope measures rise over run, such as 6:12, while pitch compares the rise to the full width of the roof. In most residential roofing discussions, pitch generally refers to slope.

What is considered a low slope vs a steep roof?

Roof slope categories typically include flat roofs at 2:12 or less, low-slope roofs from 2:12 to 4:12, conventional slopes from 4:12 to 9:12, and steep-slope roofs at 9:12 and higher. Low-slope roofs require different materials because water drains more slowly.

Does roof slope affect cost?

Yes. Steeper roofs are typically more expensive due to increased labor, safety requirements, and material handling. Very low-slope roofs can also increase costs because they often require specialized materials and installation methods.

Roof Slopes Explained: A Simple Guide to Pitch and Performance

Q: How does roof slope affect roofing materials?

Roof slope determines which materials can be used. Steeper roofs can handle shingles, metal, and tile more easily because water sheds quickly. Low-slope roofs often require specialized systems such as membranes to prevent leaks.

The shape of your roof impacts more than just the look of your exterior; it can contribute to the cost of upkeep, the labor required for a roof replacement, and the overall lifespan of your roof system. The first thing your roofer does is determine your roof slope by calculating how steep the sides of your roof are.

Let’s take a look at what your roof slope is and why it matters in the upkeep of your home.

What is Roof Slope?

Roof slope, also known as pitch, is a simple calculation of how far your roof rises from the base of your roof system to the top.

Image with the various types of roof slopes answering What are the types of roof slopes

How Do You Determine Slope?

To determine the slope or pitch of your roof, you must know a simple calculation:

Roof Slope = Rise/Run

Where:

Rise = how many inches the roof goes up
Run = how many inches the roof goes across horizontally

So if a roof has a 6/12 slope, that means for every 12 inches of horizontal increase, it goes up by 6 inches.

What Are the Different Kinds of Slope?

Flat Roofs: 2/12
Low-Slope: 2/12-4/12
Conventional Slope: 4/12-9/12
Steep-Slope: 9/12 and higher

Flat and Low-Slopes

At the lower end of the roof-pitch spectrum are the appropriately named flat and low-slope roofs. These typically go no higher than 4/12.

Common roofing materials on low-slope roofs include single-ply membranes and built-up roofs, both commonly used in commercial construction.
Flat and low-slope roofs are typically easier to install and require fewer roofing materials and less labor, making them popular in industrial areas where space and efficiency are top priorities.

Conventional and Steep-Slope

On the other end of the slope spectrum are conventional and steep-slope roofs. The higher pitch, ranging from 4/12 to 12/12, makes these roofs a better fit for shingle and tile roofing. The advantage of these materials is that there are more varieties and options with which to personalize your roof. High-pitched roofs also enhance your curb appeal with a wide selection of colors, patterns, and styles. While steeper roofs may cost more in labor, they typically require less upkeep and fewer repairs.

Get an Estimate Without the Pitch

The slope of your roof impacts the cost of the job, the amount of upkeep you will need, the look of your home, and its overall lifespan.
To learn more about your roof and get a knowledgeable estimate you can trust, call AIC Roofing & Construction for a free estimate today.

Frequently Asked Questions About Roof Slopes

Roof slope is the steepness of a roof, measured by how much it rises vertically for every 12 inches it runs horizontally. For example, a 6:12 slope means the roof rises 6 inches for every 12 inches of length.

Roof slope and pitch are often used interchangeably, but technically, they’re different. Slope measures rise over run (like 6:12), while pitch compares the rise to the full width of the roof. In most residential roofing conversations, “pitch” just means slope.

Flat Roofs: 2/12
Low-Slope: 2/12-4/12
Conventional Slope: 4/12-9/12
Steep-Slope: 9/12 and higher

The slope determines what materials can be used. Steeper roofs can handle shingles, metal, and tile more easily because water sheds quickly. Low-slope roofs often require specialized systems like membranes to prevent leaks.

Yes. Steeper roofs are usually more expensive because they require more safety equipment, labor time, and material handling. However, very low slope roofs can also increase costs due to specialized materials and installation methods.