Abstract

External Thermal Insulation Composite Systems (ETICS) are nowadays often used in new constructions but are also one of the most frequently used thermal retrofitting solutions for buildings.These systems have several advantages such as low installation cost, ease of application and increased thermal efficiency. Nevertheless, a number of questions have been raised on their long-time durability particularly related to biodeterioration. Biological growth is strongly influenced by several parameters, such as water content, temperature, pH but also by the type and hygroscopic properties of the building materials. It is therefore essential to understand and correlate those properties with biological growth. This paper aims at evaluating some ETICS characteristics that might influence surface mould development which is recognized as one of the major groups of deteriorating organisms. The susceptibility of the surface finishing layer and thermal insulation to biological growth was assessed through natural inocula and selected fungi and, whenever possible, correlated with water absorption and drying capacity. This study is part of a wider research project: WGB_Shield (Shielding building‘ facades on cities revitalization. Triple-resistance for water, graffiti and biocolonization of external thermal insulation systems) that aims at the development of ETICS with improved durability in the urban environment. Further development on this issue are ongoing.

Abstract

Mould growth is a biodeterioration phenomenon that jeopardizes the integrity, functionality and durability of building envelopes. The performance to withstand biodeterioration depends on the critical hygrothermal conditions inside the envelope. These conditions are subject to the configuration of building envelopes, and climate exposure, accounting for both the outdoor weather and indoor environments‘ conditions. These critical conditions are likely to intensify in response to the changing climate, and hence, modification and adaptation of the envelopes‘ configuration will be required. An understanding of the implications of envelope configurations‘ choices is required to set up guidelines for forthcoming building envelope design. Parametric analyses are a potent source of insight to investigate how the input parameters influence the desired outcome. In light of this, a parametric analysis is carried out to investigate the performance of three building envelopes to withstand mould growth. The impact of climate change in the performance evaluation is accounted for by employing both historic and future climate change scenarios in which the global climate temperature change is forecast to be 3.5º C. Input parameters related to the simulation of mould growth are also investigated. Recommendations to current building envelope design guidelines are drawn for the performance evaluation to withstand mould growth