“The bearing walls like a “natural thermal governor”: the case of “Sassi di Matera”

The bearing walls represent one of the most ancient technological systems in the building process; in fact, the built heritage, historical or monumental, is realized within this particular kind of solution. It’s a simple structural system, but it possesses high quality technical and technological characteristics that makes it competitive; just think about the low impact that it produces on the surrounding environment, the low CO2 loading that it releases in the atmosphere during its cycle of life and, furthermore, the possibility to recycle its component. This research involved the values expresses by this particular kind of architecture and the indoor quality produced. Today, while projecting, it is very important at first place to consider the definition of the quality parameters of the indoor air and comfort requested to a dwelling place. We did this with tests “in situ” by monitoring the indoor comfort (as requests by the low UNI EN ISO 7730 1997 e UNI EN ISO 7726 2002 , directive CEE n° 106/89). This research looks at demonstrating that the bearing walls operate like a “natural governor” of the thermal and hygrometrical comfort and are able to give high quality performances, even without the support of technological systems. The characteristic performances of these spaces, that today are utilized in different ways as regards the original use, are tested and monitored. The testing activity was verified through experimental applications in the restoration of two urban buildings in the ancient “Sassi” in the town of Matera (Italy); they represent two typological structures characterized by bearing walls made of limestone blocks. The space and structures analyzed demonstrate what said before, showing how these building are suitable to the requirements of performances and quality requested for the residential environments (European Directive 2002/91/CE and Italian low D.lgs 192/05 – 311/06) even if they are built with traditional technologies.