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Home | How to do it | How To Calculate Roof Pitch

How To Calculate Roof Pitch

Remember all of those math classes you took as a student? They’ll come in handy now when you try to calculate the size and pitch of your roof. Whether you’re a homeowner trying to figure out how much a new roof might cost or a beginner contractor learning how to measure customers’ roofs for the first time, you’ll need to know how to calculate pitch before you begin any roofing project.

Calculator leaned on a little house with red roof. 3d rendering

At Legacy Service, we want you to succeed and be happy with how your project turned out. This article is to inform you about how to determine the roof pitch on a home, so you can accurately measure its size and figure out the materials you’ll need for installation or replacement. Use the methods of the roof pitch calculator that we’re about to teach you and you’ll be ready to go in no time!

Once you learn these methods, get out there and start installing those roofs. If you’d like to learn more about our team at Legacy Service and what we can do for you or your home, contact us here or give us a call today at 215-798-9790.

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What is the Pitch of the Roof?

Roof pitch is a term that’s used by roofers, architects, and contractors to describe the slope or steepness of a roof. It refers to the amount of rise (the vertical measurement) a roof has compared to run (the horizontal measurement). It’s typically represented in inches rise of 12 inches run, so a 4 pitch, 4/12 pitch, or 4 in 12 roof pitch all mean that the roof rises by 4 inches for every 12 inches of horizontal run. By using the pitch, its footprint, and simple geometry, you can quickly and accurately calculate the length of the sides, allowing you to get precise area measurements.

While roofs have many attributes, the pitch is important in determining the cost of replacement as well as the correct materials to use. It’s also useful when you’re designing an addition for your home, installing skylights, or cutting new rake boards.

Remember that when you measuring the pitch of a roof, it’s best to do it on a bare roof because curled up shingles can impair your measurement. If this isn’t possible, you can perform the measurement on the underside of the roof.

Why It’s Important to Calculate Pitch

Calculating the pitch of your roof is one of the most important things to do before beginning the project. As we previously mentioned, accurately calculating the pitch of your roof will help you determine which materials would be right for the job as well as the potential price range.

Although a roof can be measured in degrees, it’s often simpler, faster, and more accurate to calculate the pitch. There are a couple of Do-It-Yourself methods for measuring the pitch of a roof, which we’ll go over later this blog. One of the methods is more accurate while the other is usually quicker and easier. The reason for this is that the first method involves climbing up on the roof while the second one allows for a quick calculation when there’s no ladder available or you need to quickly estimate the size or price of the roof.

Categories of Roofs

Roofs can be categorized depending on their pitch. Here are the four main ones:

  1. Flat – This type of roof is not completely flat because they still need a small slope for water runoff. Their pitch is typically between ½:12 and 2:12.
  2. Low-pitched – This type can be difficult to maintain since it requires special materials to avoid leaks. The pitch is typically below 4:12.
  3. Conventional – This type is the most popular. It’s the easiest one to reconstruct and the safest to walk on. The pitch usually ranges from 4:12 to 9:12.
  4. High-pitched – This type typically requires additional fasteners. The pitch can be as high as 21:12.

Roof Pitch Degrees

If you’d like to know how to convert roof pitch to degrees, check out the chart below:

1-12 4.76°

2-12 9.46°

3-12 14.04°

4-12 18.43°

5-12 22.62°

6-12 26.57°

7-12 30.26°

8-12 33.69°

9-12 36.87°

10-12 39.81°

11-12 42.51°

12-12 45°

Standard Pitch

Roof pitches will vary depending on the climate you live in, your style, and the available materials, so there’s actually no standard roof pitch. However, if you’re living in the United States, the range of standard pitches is typically between 4/12 and 9/12.

Minimum Pitch

If you live in a snowy area, you’ll probably need a steeper pitch for your roof. The minimum for shedding snow should be about a 6:12 or 7:12 slope or about 30°. This isn’t definite, though, since the material of your roof and the direction of the wind and snow can affect whether the snow will slide off or not. In fact, some roofs of about 10° can even shed snow.

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How to Calculate Roof Pitches

Now that you know what the pitch of a roof is and why it’s important to calculate it, it’s time to learn how to calculate the pitch. As we previously mentioned, there are two basic methods of how to measure a roof’s pitch:

Method 1 – Using a level and measuring tape.

For this method, you’ll need a ladder that can reach the roof’s edge, measuring tape, and a 2-foot level. Remember to be safe when climbing the ladder and make sure you have adequate fall protection. A ladder stabilizer is also recommended to help prevent it from sliding side to side.

Once you’re at the top of the ladder, hold your level so one end touches the surface of the roof and the other is in the air. Keep it level. Then, measure the distance between the roof’s surface straight down from the level’s opposite edge.

Method 2 – Estimate the pitch from the ground.

Although this process is typically quick and easy, we recommend getting a more accurate pitch measurement if you’re planning to order materials. Fortunately, the first method is good for that.

However, if you’d prefer to get a quick estimate, it’s much easier to use this method. To do this, you’ll measure the width of the roof on the gable side and the exposure of your siding. Since most siding has 4” exposure, which means that every three runs of siding will give you one foot rise. Then, you’ll need to determine the number of runs on your siding from the base of the roof. And since most homes have a 6” rake board along the roof line, you’ll have to add about 7-9” to the roof rise.

It’s Time to Get Started!

If you need help getting started calculating the pitch of your roof, contact our team here at Legacy Service. We have decades of experience in working with home exteriors, whether it involves roofing and siding or windows and doors.

We care about the quality of your roof, so our job doesn’t just stop when the roof’s installation or replacement is finished. We’ll take care of you and your home from start to finish and communicate with you every step of the way. To get started with your roofing project, contact us here or call our team at 215-798-9790.