Nailing consist of structures made through laying of resistant elements (such as steel bars) laid in holes specially made in risk slopes. The drilling techniques and procedures for anchoring to the ground are defined according to the materials to be crossed. The specific specialized equipment, transportable by helicopter, are very strong but light enough to be used in the wall.
Passive nailing is used in net laying interventions on an uneven surface on the three Cartesian axes. The aim is to make the net adhere as much as possible to the rocky surface.
Active nailing is used for surface reinforcement along rocky slopes in a simple mode or reinforced by a net of ropes - bandage or sling of single rocky elements which are disjointed or isolated.