Effects of hygrothermal, UV and SO2 accelerated ageing on the durability of ETICS in urban environments. (15th October 2021)

• Record Type: Journal Article
• Authors: Parracha, João L.; Borsoi, Giovanni; Veiga, Rosário; Flores-Colen, Inês; Nunes, Lina; Garcia, Ana R.; Ilharco, Laura M.; Dionísio, Amélia; Faria, Paulina
• Is Part Of: Building and environment. Volume 204(2021)
• Publication Date: 2021-10-15
• Subjects: ETICS -- Durability -- Artificial ageing procedure -- Surface properties -- Mould susceptibility -- Surface wettability; Buildings -- Environmental engineering -- Periodicals; Building -- Research -- Periodicals; Constructions -- Technique de l'environnement -- Périodiques; Electronic journals; 696
• DOI: 10.1016/j.buildenv.2021.108151
• Languages: English
• ISSNs: 0360-1323

Abstract

Abstract: External Thermal Insulation Composite Systems (ETICS) have been extensively used for either new constructions or building facades retrofitting in the last decades. These systems can provide improved thermal performance to the building envelope. However, their long-term durability remains a pervasive concern, with some systems presenting relevant anomalies after few years from their application. The durability assessment of ETICS is defined by the EAD 040083-00-0404 guideline, which stated an accelerated ageing procedure based on the hygrothermal and freeze-thaw behaviour. Nevertheless, further important environmental urban conditions, such as UV radiation and atmospheric pollutants, as well as bio-susceptibility, are not envisaged in the guideline. This paper presents the results of an experimental campaign with the aim of evaluating the durability of the rendering system of several commercially available ETICS exposed to an innovative accelerated ageing procedure, which consists of hygrothermal cycles, UV radiation and air pollutants (SO2 ) exposure. Physical and chemical-morphological tests were carried out prior and after each ageing cycle in order to evaluate the durability of ETICS. Biological susceptibility to moulds was also assessed. The experimental results showed that both surface hardness and surface gloss decreased after the combined effect of the hygrothermal, UV, and SO2 ageing cycles, whereas an increase of surface roughness was observed. Substantial colour change for all systems after the ageing procedure was observed, confirming aesthetic alteration. Traces of biological growth were detected on the systems after ageing and the contact angle decreased after the hygrothermal cycles, indicating a lower surface hydrophobicity of the systems. Graphical abstract: Image 1 Highlights: An ageing procedure for the evaluation of the durability of ETICS is proposed. The durability is assessed by considering the variation of ETICS condition prior and after each ageing test. Mould susceptibility of ETICS after ageing is investigated. Hygrothermal cycles have a significant impact on the surface properties of ETICS.