Environmental and Economic Performance of Asphalt Shingle and Clay Tile Roofing Sheets Using Life Cycle Assessment Approach and TOPSIS Solomon Sackey 1 and Byung-Soo Kim, Ph.D. 2 Abstract: The construction industry utilizes many materials that go through different manufacturing and transportation processes. Selecting and using environmentally friendly or green building materials is one way to reduce the inimical environmental effects associated with the construction industry. However, environmental preference cannot be used as the only criterion in selecting a building material. As cost is an important factor, environmental performance needs to be balanced against the economic performance. The decisions on material selection, therefore, need improvement. This study analyzed and compared the environmental and economic performance of asphalt shingle and clay tile roofing materials using the building for environmental and economic sustainability (BEES) model. The results were then used to develop a combined performance score using the technique for order preference by similarity to ideal solution (TOPSIS) to assist decisions pertaining to the selection of the best material based on the performance score. To present another decision criteria to compare and select a roof material, the study utilized the contingent valuation method (CVM) to estimate the environmental cost associated with these alternative materials. The simulation results showed that clay tile had a better environmental performance score of 0.3525 points ðptsÞ=unit compared to the score of 0.4135 pts=unit for asphalt shingles; however, asphalt shingles had a better overall performance score of 0.5985 pts against 0.4153 pts for the clay tile. Merging environmental and economic considerations to a common score as presented in this study will help improve and contribute to the quality of decision making in that it provides a substantial basis to select the most suitable, cost-effective roofing material. DOI: 10.1061/(ASCE)CO.1943-7862.0001564. © 2018 American Society of Civil Engineers. Author keywords: Life cycle assessment (LCA); Asphalt shingle; Clay tile; Technique for order preference by similarity to ideal solution (TOPSIS); Economic performance; Environmental performance. Introduction Research Background The construction sector is extensive and consumes a large volume of raw materials. Asphalt shingles are one of the building products that use a large number of materials in their production. The global contribution from buildings, including both residential and com- mercial, toward energy consumption has steadily increased, reach- ing between 20% and 40% in the developed countries, and it has exceeded that of other major sectors such as the industrial and transportation sectors (Pérez-Lombard et al. 2008). Building and construction activities worldwide consume 3×10 12 kg (3 billion tons) of raw materials each year or 40% of the total global use (Tudora 2011). According to the report by the Korean government on the climate change cited in the study by Sim et al. (2016), ap- proximately 23% of carbon dioxide emissions occur in the Korean building sector alone. As the demand for building infrastructure continues to rise, the search for different building materials will also continue to gain momentum. Modern advanced technology has consistently helped to improve the traditional uses of local building materials by adding a variety of features to the materials to enhance their performance and aesthetic look. Roofing materials, for instance, have seen such a transformation. A roof covering is provided for shade, for protection against the rain or other natural elements, or for other shelter purposes [J. P. Lynch, “Collapsible canopy with auto erect roof support structure, ” US Patent No. 4,947,884 (1990)]. In buildings, roof covering can cover more than 60%–70% of the building surface (D’Orazio et al. 2010). Accord- ing to Bretz et al. (1998), the roofing market data indicate the roofing materials that should be targeted for incentive programs. The researchers found out that asphalt shingles were used for over 65% of residential roofing area in the United States and 6% of commercial roofing in 1995. Similarly, built-up roofing was used for about 5% of the residential roofing and about 30% of the com- mercial roofing. The ever-increasing demand for products is putting more pres- sure on the environment. As resources and manufacturing products continue to be exploited, potential devastating stresses on the natural world can occur. In the research conducted by Senitková and Bednárová (2015), they found that the construction industry depletes about two-fifths of global raw stone, gravel, and sand and consumes 40% of the total energy and 16% of the freshwater annually. In this study, the environmental and economic perfor- mance of asphalt shingles and clay tiles is investigated. In other to reduce the environmental impact of the building sector, it is vital to consider the environmental impact of the individual products or materials making up the building facility. However, the issues of the environmental performance and economic performance of building materials continue to be some of the debated topics. While some 1 Dept. of Civil Engineering, Kyungpook National Univ., 80 Daehakro, Daegu 41566, Korea. Email: s.sackey123@knu.ac.kr 2 Professor, Dept. of Civil Engineering, Kyungpook National Univ., 80 Daehakro, Daegu 41566, Korea (corresponding author). Email: bskim65@knu.ac.kr Note. This manuscript was submitted on December 4, 2017; approved on May 31, 2018; published online on September 12, 2018. Discussion period open until February 12, 2019; separate discussions must be sub- mitted for individual papers. This paper is part of the Journal of Construc- tion Engineering and Management, © ASCE, ISSN 0733-9364. © ASCE 04018104-1 J. Constr. Eng. Manage. J. Constr. Eng. Manage., 2018, 144(11): 04018104 Downloaded from ascelibrary.org by Byungsoo Kim on 09/16/18. Copyright ASCE. For personal use only; all rights reserved.