Retrofitting of ETFE roofs

ETFE is one of the most stable chemical compounds and its films are largely employed in the building industry due to the very good long-term stability, resistance to soiling and high light transmittance. The mechanical strength is relatively good, especially considering that the material is not reinforced by a woven support, and make ETFE foils suitable for load bearing envelopes characterised by small spans or supported by cables [1]. ETFE foils are traditionally used for multilayer pneumatic cushions, however, in recent projects the application of single skin ETFE foils has been successfully investigated. This innovative application opens new areas of interest in the area of the building envelope, such as a protective secondary facade. In addition, the growing demand for reducing the heating\cooling costs has recently increased the demand for ETFE foils with pigments or surface treatments able to improve the environmental performance of lightweight envelopes based on ETFE foils [2]. This research paper describes the thermal performance of an existing ETFE roof in Verona and the subsequent retrofitting of the structure in order to meet the targets of solar shading specified by the client. The paper includes the data obtained through the monitoring of the structure before and after the installation of a new set of cushions manufactured with a bespoke silver ETFE designed in order to reduce the solar gains and improve the overall level of comfort during the warm season