Natural Stone on ventilated facades, beauty to the service of architecture

The ventilated facade is one of the most energy efficient of the existing facades. This system produces considerable energy savings and makes the inside of the building much more comfortable.

There are many different types of ventilated facades, a secondary covering on the walls of a building which makes it sustainable, but we do not intend to talk about this in this article, we are instead going to talk about the size of the natural stone used.  But … How many things do you think affect the size of the natural stone?

The first and most decisive factor is the shape of the facade. We always try to ensure that the stones have the same dimensions and that they fit the apertures in the facade, for example those for the windows.
The next most important factors are the physical-mechanical characteristics of the stone, mainly the mechanical strength of the stone (flexural strength) and its density.

There are also the dimensions of the tile. The thinner the tiles are, the greater the forces they will have to withstand and the thicker the tiles will have to be. Fortunately these forces decrease if the tile has more anchors. The maximum height of a tile will be determined by the dimensions of the slab. If this is 2.4 m high and 1.4 wide and there is a gap of 1m between the anchors, then the required thickness will be 25 mm. If we reduce the gap between the anchors to 0.8 m the required thickness will be 20mm. We also have to bear in mind that the more weight the fixings on the ventilated facade have to support, the greater the installation costs will be.

What we have just considered are the factors related to the stone itself. The external factors which test flexural strength are as follows:

Wind speed exerts pressure on the stone and this may well be considerable. The wind speed in turn depends on the height and robustness of the building. For example the thickness required to support wind pressure for the same size of stone increases from 19mm at a height of 3m to 25 mm at 30m. Exposure to the wind will also be greater if the building stands on its own or is on the sea front, as opposed to in an urban environment.

Temperature changes also affect the stone negatively. The required thickness in Spain will be less than that in Northern Europe, for example, which has a harsher climate.

We have now looked at the factors which influence the dimensions of the natural stone in a ventilated facade. You had no idea there were so many, did you?