An integrated process for rehabilitating historical buildings

This paper reviews the energy upgrading of historical buildings and its relationship with structural rehabilitation. Regarding the structural aspects, over the last 20 years a correct culture of architectonic conservation has revealed the inadequacy of such commonly used intervention techniques as injections with reinforced concrete and cement string-courses. Nonetheless, such techniques continue to figure largely in the approaches of both professional consultants and builders, and the damage they cause is patently obvious. However, there is also a significant methodological aspect involved, for they radically alter the ancient construction concept, which down the centuries has proved capable of withstanding both natural and man-made calamities. Unfortunately structural damage is all too often compounded by alteration of the thermo-hygrometric parameters of the walls, leading to the formation of condensation in correspondence with the cement structures. More insidious still, because it is invisible, is the formation of condensation in the interstices within the structures, causing oxidisation of the reinforcements. Nor, finally, should we ignore the problems of rising damp and damp entering from surrounding earth, which may occur in correspondence with walls embedded in the ground or built against embankments. Regarding the energy aspects, a number of energy saving techniques are available, but unfortunately many of them cannot be used in historical buildings on account of historical and architectural constraints. Last but not the least, the essential features of Indoor Environmental Quality (IEQ), above all thermic comfort and Indoor Air Quality (IAQ), are costly in terms of energy consumption. This paper presents an analysis of the thermal and structural behaviour of the building and the proposals for sustainable rehabilitation interventions. The goal is to achieve environmental comfort conditions and reduce energy consumption by applying sustainable strategies regarding both the building envelope components and the HVAC systems.