How to calculate the quantity of tiles needed for your construction site?

The tiling is available in an extremely rich palette of models and colours, for indoors or outdoors. It is not surprising that it is still so popular, because it allows you to create varied universes and to take care of your decor. From the kitchen to the bathroom via the terrace or the balcony, tiling is one of the big trends. But before attacking the work, it is essential to carefully determine the quantity of tiles to buy. Not so simple for DIY neophytes.

Formula to apply to know how much tile to buy

The basics to know before embarking on this type of project is the surface to be tiled. In order not to be mistaken, it is imperative to start with a layout.

The required tiling area is calculated by multiplying the length of the area to be tiled by its width. So for example, for a sol 5 m by 7 m, the surface is therefore 35 m². But that’s not all ! If we have to ask wall tile, it is obviously necessary to subtract the space occupied by the windows, bay windows, doors and other parts which will not be tiled. It is therefore necessary to take their measurements precisely in order to calculate the area that all these areas represent.

Pour tile baseboardswe no longer speak in square meters but in linear mothers since a single tile in height is sufficient over the entire length to be covered. We therefore measure, for example, the perimeter of the room concerned and then we subtract the doors in order to know the length of the sections of walls that require a tile skirting. For example, for a baseboard in a rectangular bathroom measuring 3.50 m by 4 m, we obtain: (3.50 x 2) + (4 x 2) = 15 linear meters from which we subtract 0.80 cm for the door if this is the case, either in fine 14.20 linear meters.

Whether calculated in square meters or in linear meters, the number of tiles to buy is to be determined taking into account the size of each. In this area, the consumer really has a choice, from small tile of 5 x 5 cm, i.e. 420 tiles/M² or 25 for 1 linear meter, at large tile 60 x 60 cm, i.e. 3 squares/m² or 2 per linear meter.

Of course we can seek advice from a professionalor even make him establish a quote if you prefer that he take care of laying the tiles himself.

Why do you have to buy a little more tile than necessary?

We advise not to be stingy when you want to lay your own tiles. In fact, when ordering equipment, it is better to plan wide. This is necessary so as not to be faced with a rupture de stock in case you have to buy a few tiles to finalize your site. By taking this precaution, we also avoid being confronted with a shade difference between the tiling already laid and the one ordered afterwards.

It is exactly the same for cutting. However, if one lacks practice, the broken is almost inevitable. It is therefore important to have a few more tiles than expected for compensate for the loss.

Another problem arises, namely that of joints. Generally, there are 3 mm joints on average, but for a style effect, it is quite possible to create joints a little wider. On very large surfaces, at least 120 m², the joints between the tiles laid on the floor are 5 mm. But whatever the surface concerned, they should never be less than 2 mm. It should be remembered that the choice may be dictated by an aesthetic need, but that does not prevent respecting the set standards that can be found by going through the Unified Technical Documents (DTU).

These seals are used, for example, to compensate for dimensional tolerances but also to neutralize, during a change in temperature for example, the material stresses. The size of the joints therefore depends on the type of tiling, its size, the nature of the support, the environment (interior, exterior), the risk of temperature variations (floor heating, etc.) and the types of installation, glued or sealed.

  • For a glued downthe standards are:
    • Inside: 4 mm (normal joint) and 2 mm (rectified tiling),
    • Outside: at least 3 mm and 5 mm obligatorily for a tiled floor covering.
  • For a sealed installationthe seals must be:
    • at least 2 mm for a tiled surface of less than 120 m²,
    • 5 mm if the surface is greater than 120 m².

Attention, while respecting the standards it is important that we take care of the final render. For example, a thick seal not suitable for a designer decor that requires joints fins when laying tiles with a rectified edge.

The type de pose also matters a lot in this area. For example, professionals specializing in tiling recommend buying approximately 15% more tiling if one opts for an alternating pose or for an oblique pose. This “consumes” more tiles due to the many cuts to be made. So to cover 50 M² with staggered tiles, we order enough to cover 75 m² (i.e. 50 x 1.5), that is to say one and a half times the surface.

If all the tiles have not been used once the job is done, most DIY signs can take back the excess. However, it is better to make sure before placing your order. Finally, the pros are unanimous on the fact that it is necessary buy your tiles in one go if you want to avoid being confronted with differences in baths (colours) but also in calibration (sizes).

In any case, laying tiles is not so simple. If you do not feel capable of it, so as not to waste your energy or your money, the good idea is to entrust the work to a pro. Simply request multiple quotes to different tilers using a online comparator and make an appointment.

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