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How Do I Measure The Pitch Of My Roof

How To Measure The Pitch Of A Roof

How to Measure the Pitch of a Roof

Pitch is a common term used in the roofing industry, but what exactly does it mean? The pitch of a roof refers to the measurement of its slope expressed as a ratio. Determining the pitch of your roof will tell you how many inches the roof vertically rises for every 12 inches it extends horizontally.

There are many reasons to know the pitch of your roof. Maybe you are considering a roof replacement or are thinking about adding skylights or other additions. To ensure that the project is successful, you need to know how to measure the pitch of a roof.

How To Calculate Your Roof Slope

Measuring your roof pitch is as simple as using the rise over run equation, the rise being the vertical component and the run being horizontal. For every foot that your roof extends horizontally, it rises by “x” amount of inches. To determine the “x”, you can use a simple measuring technique.

After safely accessing your roof, measure 1-foot up from the base of the roof using your measuring tape, this will give you the horizontal run.

Place the end of the level at the 1-foot mark but make sure it is creating an “L” shape. Meaning, one of the bottom corners of the level touches the roof but the other bottom corner is suspended in the air.

Once the bubble of air in the level is in the middle, measure from the bottom of the level to the top of the roof. This will give you the vertical rise.

For example, if what you measured for the “rise” is 6 inches, then the roof pitch is 6/12, meaning for every 12 inches of horizontal length of the roof, the roof rises 6 inches. Steeper pitches will have a higher rise number, say 10/12, versus lower pitched roofs which can be as low as 2/12 for roofs with asphalt shingles, but can be even lower for metal roofs or gambrel style homes with roofs that have many different shaped pitches.

Why Is Calculating Roof Pitch Important

Calculating roof pitch is important because if youre contemplating a room addition or putting in skylights or cutting new rake boards , you need to know the pitch of the roof. Its also important to the roofs durability over time and how water and debris are eliminated from a roof.

The pitch of a roof also affects the costs of installing or replacing a roof. A steeper roof is going to cost more to install, so you want to keep that in mind when youre calculating the right pitch for your project. When you think of a low-slope roof, it might cost more to install than a flat roof. A steep-slope roof can cost considerably more to install.

With other home projects that involve dealing with a roof, you need to know your roofs pitch just to figure out the materials and tools youll need to do the job, plus a contractor has to consider the walkability in connection with the materials to use. Whether youre replacing your roof or installing a completely new roofing system with windows, youll need to know the pitch of your roof.

Read Also: How To Place Shingles On Roof

Three: Measure The Total Rise And Run

If you know the total height of the peak and the roofs width, you can also find the pitch with a little math. For example, if the peak is 4 feet and the total roof width is 20 feet, then the total rise is 4 feet, or 48 inches.

The total run is the distance from the peak to the edge of the roof, which in this case is the total width divided in half, which is equal to 10 feet or 120 inches.

Since the pitch is the rise over a 12-inch run, you can divide the run by 12 to get the multiplier, in this case, 120 ÷ 12 = 10.

Then, divide the rise by the multiplier to get the pitch, e.g. 48 ÷ 10 = 4.8. The pitch of this roof is 4.8:12. The calculator above can handle much of this math.

What Is The Average Quote For Getting A Roof Pitched

How To Determine Roof Pitch

There are a lot of factors that will affect how much getting your roof pitched will cost design, style, accessibility, cost of labor etc. In the USA, you can expect to pay between $3.19-$4.43 per sq.ft. for asphalt shingles. If you choose another material, such as metal or wood, the range is $7.35-$10.73 per sq.ft.

In the UK, the price of getting a roof fitting is £72-£75 per square meter. These are only estimates though, talk to your neighbors to see what roofing costs in your area.

Read Also: Does Home Warranty Cover Roof

What Is A 4/12 Roof Pitch

A 4/12 is a roof slope that rises by 4 inches for every 12 inches across. This forms an angle of 18.5° between the horizontal section and the roof, and creates a gentle incline that is seen as a midpoint between a low-pitch and medium-pitch roof. A 4/12 slope is enough to accommodate water runoff, but is not suitable for regions that are affected by heavy snowfall. Standard asphalt and composition shingles are the best for a 4/12 roof rubber and wood shingles are unsuitable.

What Is The Pitch Of The Roof

Roof pitch is a term thats used by roofers, architects, and contractors to describe the slope or steepness of a roof. It refers to the amount of rise a roof has compared to run . Its 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. Its also useful when youre designing an addition for your home, installing skylights, or cutting new rake boards.

Remember that when you measuring the pitch of a roof, its best to do it on a bare roof because curled up shingles can impair your measurement. If this isnt possible, you can perform the measurement on the underside of the roof.

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Roof Calculations Of Slope Rise Run Areahow Are Roof Rise Run Area Or Slope Calculated

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Roof slope, pitch, rise, run, area calculation methods:

Examples of simple calculations of stair or roof slope by several methods.

This article series gives clear examples just about every possible way to figure out any or all roof dimensions and measurements expressing the roof area, width, length, slope, rise, run, and unit rise in inches per foot.

Page top sketch of various roof slopes is provided courtesy of Carson Dunlop Associates, Toronto.

We also provide an ARTICLE INDEX for this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.

The Roof Pitch Calculator Input Options

How to Calculate Roof Pitch

Pitch – This option places the Rise and Run fields into the Input section. The pitch is represented as the number of inches of Rise for every 12 inches of Run.

Rise – This option places the Run and Pitch fields into the Input section, and moves the Rise field to the Results section. Select this option if you know the rafter’s Run and the roof’s Pitch, and need to determine the Rise of the rafter.

Run – This option places the Rise and Pitch fields into the Input section, and moves the Run field to the Results section. Select this option if you know the rafter’s Rise and the roof’s Pitch, and need to determine the Run of the rafter.

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How To Calculate Roof Pitch In Degrees

There are a few ways to measure or work out the pitch of your roof. All youll need to hand will be a measuring tape, spirit level and calculator. With these tools in hand you just need access to your loft space and to remember some of the maths you learned at school.

  • First, you need to measure the run of your roof. This is the horizontal length that spans between the peak of your roof and the wall. You can do this with a tape measure or spirit level.
  • Next, you need to figure out the rise. This is the height of your apex above the structure wall.
  • Now, divide the rise by the run. This will give you the tangent of the roof.
  • Then, divide 1 by your tangent.
  • Finally, multiply this result by 180/ and you’ve calculated your roof pitch!
  • REMEMBER: Roof Pitch = )*180/

    Example: Rise of 8m and Run of 5m.

  • Therefore, the roof pitch is 35.81°!
  • How To Measure Roof Rise

    Typical vinyl siding has 4 exposure, so 3 spans would be equal to 12 or 1 foot. Calculate the number of spans from the base line to the peak. Since most homes have a Rake wood, which is usually 6-8 wide, you can add that width to the rise.

    Example: If you have 19 spans of siding at 4 exposure of each span, and a 6 rake board, the rise would be:

    / 3 = 6 10 roof rise.

    Converting pitch to degrees can be useful in figuring out the roof geometry, or for European contractors who are not accustomed to th eUS system. See Table below:

    Also Check: How To Remove And Replace Roof Shingles

    How To Find The Tangent Using A Calculator Or A Table

    A tangent is also defined as a ratio of two lengths: the length of the side of the triangle opposite the angle divided by the length of the adjacent side of the angle.

    Watch out: when using a scientific calculator to obtain a tangent value, enter the angle in degrees as a whole number such as 38, not 0.38 or some other fool thing.

    The TAN function or table can be used to convert a road grade or roof slope or stair slope expressed in angular degrees to rise if we know the run, or run if we know the rise ONLY because we are working in the special case of a right triangle – that is, one of the angles of the triangle must be 90deg.

    You can also find free tables of every trigonometric function online, such as a tangent table that will give the value of the tangent for any angle.

    What Roof Pitch Is 30 Degrees

    Roof Pitch Calculator

    A 30° roof pitch is roughly the same as a 7/12 roof pitch. To convert from degrees to the American ratio:

  • Find the tangent of the angle, tan. This gives you the pitch of the roof.
  • Multiply the pitch by 12 to find the x in the ratio x/12.
  • Check your results with the Omni Roof Pitch Calculator.
  • Enjoy having one less thing to worry about.
  • Also Check: How Much Does A New Roof Cost In Calgary

    Making The Pitch Measurement

    Figure #1B

    Figure #1A

    All MicroMetl pitched curbs are constructed using customer provided height & pitch, combined with a 12-inch reference e.g. 1/4 in 12, 2 In 12, or 3-1/8 in 12. The 12-inch designation is NOT measured upon the surface of the roof as shown in Figure #1A, but perpendicular to the ground using a level as in Figure #1B.

    As previously noted, the level must be at least 12 inches long. Measure and mark off 12 inches from the end of your level Figure #2. Holding the edge of the level on the roof, lift the other side until the water bubble of the level is centered . Using the 12-inch mark, measure directly down to the roof That is your Pitch measurement.

    Figure #2

    You may be thinking, My roof has shingles or imperfections which could alter the pitch measurement depending upon where I measure, will that affect the measurement Yes! Remedy the problem using a quality three-foot 2×4 piece of lumber. Lay the 2×4 along the pitch Figure #2 to average out the surface imperfections, and make your measurement upon the 2×4.

    How To Determine Your Roof Pitch From The Roof

    If you want to measure your roof’s surface, you can think back to algebra class when you learned how to measure a slope as rise over run, the slope is now your roof.

    A gable roof style is one of the easiest roofs to measure since it is generally a low pitch that is even throughout the entire house. If you are not a contractor and do not need exact measurements down to the millimeter and degree angle, there is a simple way to measure your roof if you have access to it.

    • A ladder and the ability to safely sit on your roof

    Read Also: How To Repair Mobile Home Roof Trusses

    You Can Measure The Pitch Of Your Roof With A Simple Tape Measure And Level

    The pitch of your roof is the slope of the roof pane basically it refers to your roofs steepness. It is determined by finding the amount of rise per foot run, and by how many inches the slope of your roof rises for every 12 inches it runs horizontally. You can find the pitch of your roof inside by using a tape measure and contractors level thats at least 24 inches long.

    Start by placing the end of the level against the edge of the roof and extending it into the air so it becomes level. Then, measure down from the exposed end back to the roof surface and divide the results by the number of twelve inch segments on your level. For reference, any pitch greater than 3:12 is considered steep, and any pitch less than 1.5:12 is considered very low sloped.

    If you are still unsure about the pitch of your roof or how to find it, talk with one of our Product Specialists.

    The Curb Pitch Measurement Was Wrong And So Is The Curb What Do I Do

    How to Find Roof Pitch in Less than a Minute

    So whats the big deal if an RTUs not leveled! Ive heard this comment before. Heres why Like your car, the motor inside the compressor requires oil. If the oil level inside the compressor is not level, this can lead to one side of the compressors motor not being properly lubricated. Ultimately, that will cause compressor damage due to the grinding of the motors moving parts, overheating, and a reduction of efficiently.

    If you havent cut the opening in the roof yet Dont! Order a new curb. If the angle is slightly off, you can install shims to compensate. However, if the angle is too steep, dont install the RTU. Cover the opening and order an angled Curb Adapter.

    Also Check: Do I Need Plywood Under Metal Roof

    Roof Slope Calculator Example Of Use

  • Measure the run length it is the horizontal distance between the roof ridge and the wall of the building. Let’s assume it is equal to 6 m.

  • Measure the rise of your roof. Let’s say it is equal to 1.5 m.

  • Calculate the rafter length, substituting these values into the following formula:

    rafter² = rise² + run² = 1.5² + 6² = 2.25 + 36 = 38.25

    rafter = 38.25 = 6.18 m

  • Calculate the roof pitch as the proportion of rise and run:

    pitch = rise / run = 1.5 / 6 = 25%

  • Recalculate this value into an angle:

    angle = arctan = arctan = 14°

  • Finally, you can find the roof pitch in the form of x:12.

    x = pitch * 12 = 0.25 * 12 = 3

  • The pitch of your roof is 3:12. It can also be written down as 25% or 14°.

  • Roof Pitch Angles: How To Calculate Your Roof Pitch

    Image source: Action Property Inspections

    Understanding your new roof’s pitch and slope is incredibly important. This helps you understand how excess water, snow, or debris falls off the roof, which also helps guide you to the right type of shingles or roofing materials you need. We’re here to teach you how to easily calculate and estimate your roof pitch angles manually.

    Also Check: Can 1 Inch Hail Damage A Roof

    Measuring Slope From The Rafters

  • 1Access a rafter. Measuring from the underside of the roof is usually the most accurate way to find the slope, since there is no roofing material to make an uneven surface. Any of the following will give you a good measurement:XResearch source
  • A rafter in the attic.
  • The overhang of a rafter at the end of the roof.
  • A barge rafter at the side of the gable.
  • 2Position a level against the underside of the rafter. Place one end of a carpenter’s level against the underside of the rafter. Adjust the level until the bubble is centered between the two lines.Advertisement
  • 3Find the 12 inch mark on the level. If your level does not have inch marking, measure it with a tape measure and draw on a 12 inch mark.
  • 12 inches is the traditional measurement in the U.S. If you don’t have an imperial ruler, however, you can use any units. Just use the same unit for all measurements, and measure a length at least this size .
  • 4Measure the vertical distance from level to rafter. Extend your tape measure perpendicular to the level. Measure the distance from the 12 inch mark to the underside of the same rafter, directly above it. Make sure the level stays in position during this measurement.
  • 5Find the slope. The slope of your roof is the ratio of vertical distance to horizontal distance . Just write down the measurements you found. There’s no need to simplify them.
  • For example, if you find 4 inches of height with the tape measure at the 12 inch mark on the level, your slope is 4:12 or “4 in 12.”
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