Climatic comparison to analyse different degradation levels in external walls outdoor exposure

In the last few years the Durability of Building Components Group is carring out an experimental programme to evaluate Reference Service Life of self supporting external walls made of a double masonry with thermal insulation inside. In parallel with the accelerated ageing tests it was planned an outdoor exposure in order to evaluate the existing time re-scaling factor between the two kind of ageings. Analysing the different agents’ stresses which characterize the specific outdoor environment the importance to compare different degradation and performance levels on different reference outdoor exposure sites brought to realize a coupled outdoor exposure in different climatic contests. The paper deals in particular with the results obtained in exposing some specimens, analogous to the ones tested under accelerated ageing, in two cities: Milano (Italy) and Lugano (Switzerland). The two weathering conditions lead to different degradation levels. The analysis of the different climatic loads allows to relate the degradation effects with the actions. This is useful to define different Service Lives related to different outdoor weathering conditions and looking toward a better definition of accelerated ageing cycles, selecting the relevant loads, determining durability differences. To simplify and make the comparison more immediate, degradation levels have been classified using an evaluating dimensional scale from 0 (no visible damages) to 3 (presence of relevant damages such as detaches).