# Calculate the Number of Tiles in a Roof

Tiles have been used for thousands of years to make the roof of a house or building waterproof. How do you calculate the number of tiles per m²? It actually depends on the tile pattern. Explanations with the most used models.

## Model 1: calculate the number of canal tiles

The Canal tile is one of the first tiles used in construction. With a frustoconical shape, the canal tile is made up of a cover tile (the one that is placed rounded on top) and a current tile (the one that is placed rounded side down) which collects water rain.

It is suitable for flat roofs with a drop of less than 30% and is available in two models and several widths: the channel and double channel versions.

Count approximately between 18 and 55 tiles per m² depending on the model of canal tiles to be laid.

## Model 2: calculate the number of flat tiles

Widely used for roofs that have more than 40% slope.  The flat tile comes in a rectangular or beavertail shape and is made of terracotta or concrete in various colors.

Available in several sizes, it will take between 65 and 75 flat tiles per m² depending on the size chosen.

## Model 3: calculate the number of interlocking tiles

The interlocking tile is suitable for all roofs with between 25 and 60% slope. It is recommended in windy regions for its excellent wind resistance. Various shapes are possible as well as various colors and sizes.

Allow an average of 15 to 22 interlocking tiles per m².

## Model 4: calculate the number of Roman tiles

It is a cross between the Roman tile and the interlocking tile but it requires a strong frame because it has a substantial weight.

To cover one m² of roof surface, it will be necessary to provide between 10 and 15 Roman tiles per m².

## Model 5: calculate the number of pan tiles

It is ideal for very low slopes and requires only 10 pan tiles per m² for large dimensions.

## The measurements needed to calculate the number of tiles for a roof

You must know the surface of your roof which will be multiplied by the number of tiles per m² to which you will have to add a safety margin of 10%.

• The roof area is easy to calculate when it comes to a flat roof (S= length x width).
• When the roof has a slope, the length will be equal to the square root of (height of the pan² + width of the roof²). The surface will have to be multiplied by two for a classic two-sided roof.
• The calculation becomes much more complicated with a roof of more than two sides. We recommend that you hire a carpenter-roofer.

Before laying your tiles, find out about the standards and DTUs in force. Be careful, there are different DTUs depending on the tiles chosen but also the climatic regions, so to ensure that your tiles are laid according to the rules, do not hesitate to consult a professional.

In summary: Number of tiles = Roof area x number of tiles per m² + 10%

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