"I installed the air conditioning and I put white gravel, I was fed up with the weeds."
It is common to see in the south of France pavilions surrounded by a “garden” of immaculate white gravel. The fight against “weeds” is a pretext for developing the worst aberrations from a climatic and environmental point of view.
The owners of these houses do not make a link between the installation of white gravel around their house and the fact that they have the need to air-condition rooms that are sometimes relatively sheltered from direct solar radiation.
In addition to the fact that this type of mineral development cancels out the benefits of soil evapotranspiration, it considerably increases the albedo of the surfaces adjacent to the construction.
However, we know that solar gain reflected by the ground on a facade in summer can be considerably aggravated by increasing its albedo. It is estimated that a clear surface in front of a glazing can easily increase solar gain by around 25% through it.
It must be remembered that the development of the surroundings of a building has an essential thermal function and must contribute to maintaining a favorable microclimate.
No choice can be left to chance in bioclimatic design!
Sources: J. Dreyfus, J.-P. Oliva
Image: Unsplash, Khadeeja Yasser