Impact of Environmental Exposure on the Service Life of Façade Claddings—A Statistical Analysis

Joana Barrelas,Ana Silva,Inês Flores-Colen,Jorge De Brito,António Tadeu,Ilídio Dias

doi:10.3390/buildings11120615

Abstract

Façade claddings, as the outer protection layer of the building’s envelope, are directly exposed to environmental degradation agents. The façades’ orientation and their distance from the sea, among other location and protection-related factors, influence their vulnerability to climate loads, in particular wind and air humidity. These loads, as well as exposure to air pollution, affect the degradation process of claddings and the durability of façades. Therefore, studying the impact of the environmental exposure conditions on the service life of different external claddings provides useful information on their performance over time, which can support (i) decision-makers in the selection of the best façade cladding solutions and (ii) further research on the impact of climate change on building components. This study covers six types of cladding: rendered façades (R), natural stone cladding (NSC), ceramic tiling system (CTS), painted surfaces (PS), external thermal insulation composite systems (ETICS), and architectural concrete façades (ACF). Three hundred façades located in Portugal are analysed according to three main groups of variables, which characterize (i) the façades, (ii) their degradation condition, and (iii) the environmental deterioration loads and context. The statistical analysis results reveal that the environmental variables affect the cladding degradation process. South-oriented façades present lower degradation conditions than façades facing north. The distance from the sea and high exposure to pollutants add to the degradation conditions, reducing the expected service life of façades. The results reveal that claddings can be organized according to two main groups: the most durable (CTS, NSC, and ACF) and the least durable (R, PS, and ETICS) systems. This study enables a comprehensive analysis of the data, useful to draw conclusions about the influence of environmental exposure conditions on the degradation and service life of façade claddings.

Highlights

IntroductionAction of combined climate agents, such as temperature, humidity, precipitation, and wind; Location, in terms of topography, rural or urban context, altitude, and distance from the sea [2]; Immediate surrounding context, in terms of protection by vegetation or buildings
A methodology used for predicting the service life of rendered façades was developed [12,13] and the resulting model was later used as a general framework for the service life prediction of other cladding materials, including natural stone cladding (NSC), ceramic tilling system (CTS), painted surfaces (PS) [1], external thermal insulation composite system (ETICS) [14], and architectural concrete façades (ACF) [15]
Severity of degradation index (Sw ), which is calculated through the following equation: Sw = ∑ An ×∑n k a,n where Sw is the severity of degradation; An the area affected by anomaly n; kn the multiplication factor for the anomaly n; ka,n the weighting coefficient according to the relative weight of the anomaly n; A the total area of the constructive solution; and k the multiplying factor corresponding to the highest degradation condition of the area A

Summary

Introduction

Action of combined climate agents, such as temperature, humidity, precipitation, and wind; Location, in terms of topography, rural or urban context, altitude, and distance from the sea [2]; Immediate surrounding context, in terms of protection by vegetation or buildings. These factors influence the microclimate on the surface of the façade, which is critical for the degradation of materials [3,4]. Buildings 2021, 11, 615 according to the relative weight of the anomaly n; A the total area of the constructive solution (in m2 ); and k the multiplying factor corresponding to the highest degradation condition of the area A. More details on the original methodology and illustrative examples of the claddings’

Objectives

Findings

Discussion

Conclusion