How To Calculate Roof Slope: Step By Step

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Calculating the slope of the roof is a very important procedure for the entire roof design, and therefore it needs to be done with care and attention. If you want to learn how to perform this type of calculation be sure to follow the post below!

Roof Slope

By calculating the slope of a roof, it is possible to determine the height of the ridge, the length of the pendulum, and the coverage area. In addition, this information helps to define the number of tiles to be used in the work, avoiding the waste of materials.

In general, it is a simple and fast process, but as the account involves different units of measure, some confusion can arise that leads to errors in the project.

Important definitions

As we do not want any errors to happen, it is necessary to quote some important basic definitions before we calculate the slope, starting with the type of tile that will be used in the work.

The tiles can be metallic, ceramic, galvanized, polycarbonate, glass, concrete, or ecological. No matter the version, what will always determine the slope of the roof is the type of tile.

Also, be aware of the size of the tile, remembering that the smaller it is, the greater its inclination and vice versa. Regardless of the size of the material, calculating the slope will allow defining the final height of the ridge.

Another important detail concerns units of measurement. In order not to get confused and make the wrong calculation, compromising the development of the project, it is recommended to adopt a single unit of measurements, such as the meter or centimeter, for example.

Stepwise instructions on how to calculate the pitch of the roof

Now that we are aware of these very important details, let’s go step by step to calculate the slope of the roof. For this, we will use a hypothetical project, in which we need to calculate the final height of the ridge of a gable roof, with a total width of 8 meters and a 30% slope indicated by the manufacturer.

Step 1: If the roof is 8 meters wide and has two sides, the ridge will be in the middle, 4 meters wide.

Step 2: With an inclination of 30% (30/100), we will have 30cm of height for every 1 meter of width.

Step 3: Proportionally, every 4 meters in width we have 120 cm in height (or 1.20 meters, in the chosen unit).

In other words, the final result shows that the ridge will be at a height of 1.20 meters (120 cm).

Other tips

There is yet another way to make the account, using the Pythagorean formula. In the case of the example above, it would look like this:

H (height) = 4m x 30% = 1.20m

Just replace the measurements with those of the roof for which the calculation will be made.

Finally, remember that you should always check the correct slope for the tile, informed by the manufacturer, something that will make the job a lot easier. And, don’t forget that the slope of the tile is measured as a percentage and not at an angle.

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