PSI - Issue 55

Giovanna Bartels et al. / Procedia Structural Integrity 55 (2024) 88–95 Giovanna Bartels et al./ Structural Integrity Procedia 00 (2023) 000 – 000

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protecting buildings, influencing in thermal comfort, affecting the behaviour of the building and providing safe access to maintenance actions (Botejara-Antúnez, 2022). When a flat roof has a poor thermal comfort, this is a result of a bad use of this key element that contributes to thermal exchanges with the exterior. In winter, thermal comfort depends on some characteristics of the roof, such as the horizontal envelope area. However, in summer, there is a tendency for the internal building temperature to rise if the thermal insulation of the roof is not effective (Gomes. 2014). Flat roofs can also suffer significantly in the absence of proper maintenance as compromised water and moisture sealings, for instance, become pivotal weak points in the roof structure, disrupting thermal comfort. These issues extend by impacting environmental and economic variables. Over the building's lifecycle, rising energy consumption becomes apparent (Jo, 2010), leading to substantially higher operational costs due to increased maintenance demands. Despite increased emphasis on retrofitting in the past two decades, driven by guidelines, decrees, legislation, and government programs, there remains a noticeable gap in the effective thermal comfort of building occupants. This challenge also needs to be faced with innovative market solutions for flat roofs, such as the one studied in this research. The Smart Roofs System project aimed to create an improved thermal comfort solution using traditional flat roofs. They comprise the following layers: bonding material, thermal insulation, basecoat reinforced with glass fiber, liquid waterproofing membrane, and an additional reinforcement layer. The common layers are the same in all possible combinations, and they are: bonding material and basecoat reinforced with glass fiber. Beyond the focus on thermal comfort, concerns related to economic, environmental, and long-term performance aspects of the roof hold significant importance and constitute the primary subject of analysis of this paper. This article proposes to estimate the environmental impacts of the materials used through Life Cycle Assessment (LCA), its associated costs, as the demand of this process is increasing in Portugal (Marrana, 2017) and the necessary proactive maintenance, which also helps with the energy consumption of the building (Jo, 2010). This paper promotes a discussion of these aspects regarding the studied flat roof. This paper is organized in four sections, including this one. In Section 2, the methodology used in this research will be presented by discussing about the methods and data collected to the development of the LCA, the costs of each solution and the process to do the data normalization and comparison between economic and environmental aspects of the 15 different combinations of the flat roof solution. Then, the description of the approach used to determine the proactive maintenance plan will be presented. In Section 3, the data generated in the LCA and the economic aspect will be reported. Also, the normalization of the data of environmental and economic impacts will be discussed for different scenarios with different priorities. The final result presented will be the main anomalies and suggested actions to avoid and treat them in the Proactive Maintenance Plan. Section 4 presents the main conclusions of this discussion and analysis. 2. Methodology Considering the various layer configurations available for this roofing system, encompassing a total of fifteen potential combinations, we will conduct a comprehensive analysis focusing on three pivotal factors that play a significant role in shaping customers' decision-making processes: environmental impact, economic considerations, and maintenance factors. The combinations were labelled based on abbreviations representing the materials used, following the order: thermal insulation material, waterproofing layer and reinforcement. The abbreviations representing materials are going to be, respectively: MW (Mineral Wool with Primary), ICB (Insulation Cork Board) and XPS (Extruded Polystyrene); PU (Polyurethane Membrane with Water Soluble Basis) and PUD (Polyurethane Membrane in Dispersion with White Pigment); R22R (Textile Structure R22 V2: 100% Polystyrene Recycled); R23R (Textile Structure R22 V3: 100% Polystyrene Recycled), FV (Glass Fiber), R22PP (Textile Structure R22 V2: 100% Polypropylene) and NT (Non-Textile). During the conceptualization phase, the development team established the potential combinations as follows: (1) MW-PUD-R22R; (2) MW-PUD-R23R; (3) MW-PUD-FV; (4) MW-PUD R22PP; (5) MW-PU-NT; (6) ICB-PUD-R22R; (7) ICB-PUD-R23R; (8) ICB-PUD-FV; (9) ICB-PUD-R22PP; (10) ICB-PU-NT; (11) XPS-PUD-R22R; (12) XPS-PUD-R23R; (13) XPS-PUD-FV; (14) XPS-PUD-R22PP and (15) XPS-PU-NT. The methodology employed was replicated for every roof combination studied.