8. Maintenance

8.1 Origin and nature of alterations

The main types of deterioration encountered in facing can be internal to the concrete (efflorescence, for example), environmental or human-induced.

A survey conducted by CERIB shows that the most frequently reported assaults are, in descending order:

• graffiti (28%);

• damage caused by various stains (20%);

• mosses and mushrooms (20%);

• dust (15%);

• smoke and soot (8%);

• acid rain (8%).

Most of these alterations can be treated either preventively (with water repellent, for example)...