Remedial Actions and Future Trends

The aesthetic quality and durability of external building envelope could be seriously impaired by the development of microorganisms, which will colonise building materials whenever a suitable combination of dampness, light and “bioreceptivity” of the substrate occurs. The control of biodeterioration in buildings includes measures useful to eliminate the presence of microorganisms and, when possible, to delay their recurrence. The difficulty lies in applying methods that are effective against biodeteriogens but that do not have interaction with the materials of the substrates. This chapter outlines some of the consolidated or innovative approaches which aim to give a concrete answer to the biological problem in buildings, acting both on the microorganisms already disseminated and on the main causes of development. Several methods may be used, in function of the type of organism present, the materials of the substrate and its state of preservation, the construction methods of the building and the freedom and economy of the intervention. Among the traditional methods, mechanical, chemical and physical strategies for the removal of biodeteriogens have been mentioned, while a more detailed study will be done on the use of biocides and water repellents that directly act on the material to prevent it from becoming fertile ground for microorganism development. Among the innovative methods, the use of engineered nanoparticles as additives to envelope finishing materials is catching on. Strategies that include a set of practical design, construction and use of buildings, which allow acting on the environmental conditions that favour the proliferation of microorganisms will be finally reported as sustainable actions.