Retrofit of the existing buildings using a novel developed aerogel-based coating: results from an in-field monitoring

The energy retrofit of existing buildings and more in general building rehabilitation represents an important challenge in EU countries since a large part of their building stock is old, poorly insulated and affected by pathologies, i.e. mould growth, with relevant implications on users health other than aesthetical drawbacks. Unfortunately, the energy retrofit of existing buildings and particularly when dealing with historic buildings presents several issues, i.e. the compatibility between the identified solutions and the heritage value or the reduction of the internal space if internal solutions have to be adopted. An emerging solution to address the target of the energy efficiency, according to the abovementioned issues, is the application of advanced materials characterized by high thermal performance and thus allowing to keep low layer thickness. In the framework of an on-going Wall-ACE Horizon 2020 project, a set of aerogel-based novel super insulating plasters, particularly suitable for internal and external application on existing walls is under development. As far as the interior layer is concerned, so far two different aerogel-based products have been developed: an interior plaster and a thermal coating were developed respectively aimed at reducing the heating energy needs and mitigating thermal bridges mould issues. The paper reports the first results of the laboratory tests carried out on the thermal coating Moreover, a monitoring activity in a 1920s building in Torino (Italy, Lat.45°N, Long 7.65°E) was carried out to characterize the actual thermal performance of the insulating layer and to assess the technical and the hygrothermal compatibility of the intervention. The monitoring results highlight that the application of a thin thermal coating finishing layer can lead to a significant increment of the indoor surface temperature of ~1.5°C with a decrease of the wall heat losses of ~30%. Moreover, a mitigation of the effect of the thermal bridge was also observed with an increment of the node surface temperature (wall-window frame) of up to 2°C.