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Roof Pitch Chart: How to Use Roof Pitch Chart

Roof pitch refers to a mathematical expression that shows how steep a roof is.

The pitch gives the slope as a ratio of the vertical rise to the horizontal run.

The expression of the roof pitch is in the form of X:12 or X-in-12.

Figure 12 is used for the run since there are 12 inches in a foot.

The steepness of a roof can also be expressed in degrees or percentages.


How to Determine Roof Pitch

To determine a roof pitch, you need an extension ladder, a level, a ruler, and someone to assist you.

If the roof is too sloppy and slippery, then you can ask a professional to help you with this.

Here are the steps that you can take to determine a roof pitch by yourself:


Step 1

Take a ladder and ensure it reaches the top of the roof.

Tie the ladder to the fascia board to prevent it from falling.

You should exercise some caution because the roof may be slippery due to its slanting nature.


Step 2

Place the level at the center of the top ridge.

Then note the reading of the level to the bottom of the roof.

Ensure that the scale has 12 runs.

The runs indicate the inches.

The measurement at this stage is for a plain roof.


Step 3

If the roof has thick layers protruding over the roof, you need to include that in your measurement as well.

This can be done by putting the tape at the bottom of the layer and extending it to the upper part of the roofing sheet.

Depending on high the roof tiles are, they can be about 1 or 2 inches.

For instance, let’s assume the measurement you got earlier from the tape was 7 inches, then it implies that the roof pitch is 7/12.

If the roof layers protrude above the roof by 1 inch, then the total roof pitch becomes 8/12.


Step 4

Now that you are through with measuring the pitch of the roof, the next step is simpler as it involves simple mathematics.

Note down the roof pitch conversion factor that corresponds to the roof pitch that you calculated.

You can do this by using the roof pitch chart shown below.

In the example we gave earlier, the roof pitch that we calculated is 8/12, which has a factor of 1.2019 in the roof pitch table.




Step 5

Get down from the ladder and multiply the factor obtained from the table with the number of squares of the area measured.

Assuming the area is 10,000 squares, then the roof pitch would be 10,000 x 1.2019 and that gives us 12,019.

You can also determine the roof pitch by staying on the ground.

Simply measure the width of the roof on the gable side and the exterior wall sectors from one corner to the other.

You should also add the overhanging portions on the roof to the figure.


Importance of the Roof Pitch

The roof pitch determines the type of roofing materials that can be used on the roof.

It is an important factor in determining the quantity of roofing material that will be required when installing a new roof since it enables you to calculate the roof’s surface area.

Also, the roof pitch plays an important role when carrying out certain roof drainage calculations.

It also determines the roof slope factor (also known as the roof slope multiplier).

The roof slope multiplier is used to know the actual length of the rafter and roof area.

More so, the roof pitch is used in determining the hip and valley factor; a factor that is used to determine the actual length of hip and valley rafters.


How to Use Roof Pitch Conversion Chart Plans

Roof pitch conversion charts are used to know all the information that you need to give professional roofers.

If you can give them the actual chart and measurement that you like, they can work to give your home the look you crave.

The essence of the charts is to give people an idea of what the actual slope will appear on the roof.

Most people prefer roofs with steeper looks.

Steeper looks are preferred because they fit more with the ‘Golden Ratio’ that all architects work by.

The ratio 1:1:62 is the ‘Golden Ratio’ and most of the roof pitch charts that you see work to this ratio.

Therefore, you can feel more comfortable working with a professional that can work with a roof pitch conversion chart, provided they will adhere to professional standards by implementing the ‘Golden Ratio’ in the roofing project.


2/12 Roof Pitch

A 2/12 roof slope implies that the roof has 2 inches of vertical drop for every 12 inches of horizontal distance.

In other words, the roof is shallow.

This means that the roof does not shed water (unlike steeper roofs).

This is why it is important to choose the right type of roofing material.

A shallow roof can be found on a ranch house, a porch, or a shed dormer.

For this type of roof, you cannot use slate, concrete, or clay tiles (since they are loose-fitting and need a roof pitch that is at least 4/12).

The roofing options that are suitable for roof pitch of 4/12 include:

  • Asphalt shingle options
  • Metal roofing installation
  • Rolled roofing options


The roofing options above will keep a shallow roof protected.


7/12 Roof Pitch

A 7/12 roof slope implies that the roof has 7 inches of vertical drop for every 12 inches of horizontal distance.

In other words, the roof rises by 7 inches in a length of 12 inches.

It corresponds to 30.26 degrees.

Roofs with this pitch can aerodynamically withstand high wind.


Get the Right Roof Pitch for Your Home

A professional roofing company, like Raico Roofers, can help you know the type of roof pitch that is perfect for your home.

We will also help you choose the perfect roofing materials that are suitable for the pitch of your roof.

Our years of experience in offering a wide variety of roofing services will enable us to offer you a service that will exceed your expectations.

Get in touch with us today to schedule a free appointment and to learn more about how our roofing service can improve your home’s curb appeal.

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