Buildings Under the Rocks: An Interdisciplinary Approach for A Safe Conservation

Vernacular buildings have always been built by man in a strict relation with nature. This relation is particularly evident in the case of shelters built under rock protrusions, taking advantage of the natural element as a part of the building itself. Given their geological characteristics, the Western Alps are particularly rich of these type of vernacular buildings, which became a typical element of the local architecture and acquired a specific toponym (“barma”). Nevertheless, their conservation poses serious safety issues, that need a wide interdisciplinary approach to be solved. In this paper, the case of the Barma Mounastira hamlet (in northern Italy) is presented, with joint researches in architectural restoration and rock mechanics. First, the group of buildings was surveyed in its geometry, materials, decay phenomena, structural disorders. Then, the overhanging rock face was analysed starting with a geomechanical survey of the rock mass, in order to define potential instability phenomena and their implications on the safety of the Barma Mounastira site. This analysis enlighted that the three main problems for the conservation of the existing structures are strictly connected with the geological features of the site: water leaks from the rocks inside the buildings, the rock debris and soil where the structures are built are locally subjected to settlements and the rock cliff outcropping above the site can generate rock falls. The proposals for the solution of these problems could only come from an interdisciplinary approach, aimed at ensuring stability both for the buildings and for the rock face, as a first fundamental step for the preservation of an important typological witness of the past building traditions, respecting its equilibrium with nature.