Environmental and economic performance of asphalt shingle and clay tile roofing sheets using life cycle assessment approach and TOPSIS

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 (pts)/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.