Biodeterioration of Stone Monuments a Worldwide Issue

The biodegradation is a general action strictly linked in the presence of active organisms, and this is not only unavoidable but it represents a fundamental process of the Biosphere. When this process is acting on « valuable » objects, is named as Biodeterioration. The consequences surely produce a worse condition, and this process is particularly unfavourable when the object belongs to the Cultural Heritage field. Climatic factors (temperature, humidity, rain, sun exposure, and air pollutants) can establish good conditions for the development of several organisms on the surfaces, inducing first of all aesthetic damages (vegetative structures, coloured patches or patinas and crusts). Different approaches have been adopted to isolate, identify and quantify such wide group of organisms, and several methodologies and products have been used to eliminate and prevent such biological settlements. However, this field needs to subdue the sector of the qualification and to emphasise the quantification of such phenomenon. Furthermore, we have to consider this as one factor in a more general theory of Biogeomorphogenesis. A model describing the concept of stone durability, involving the Biodeterioration process, is proposed. The data of the selected parameters coming from different dominions could be integrated and elaborated in a new relational database MDDM (Management of Dynamic Durability Model). The exact knowledge of the resistance of a monumental object is crucial for a suitable schedule maintenance. Taking into consideration that the process can never be stopped but only slowed down to a minimum with balanced prevention and intervention actions.