Identifying and assessing the critical criteria affecting decision-making for green roof type selection

Green roofs are categorized into different types based on their characteristics, and each type of green roofs offers different benefits and costs for both private and social sectors. Although there are studies conducted in many aspects of green roof installation, there is lack of study focusing on decision making (DM) for green roof type selection. The aim of this paper is to identify and assess the criteria affecting DM for green roof type selection from the standpoint of multi-criteria decision making in Kuala Lumpur, capital of Malaysia. Enhanced fuzzy Delphi method (EFDM) was developed for criteria identification. EFDM consists of two rounds; firstly, knowledge acquisition through a semi-structured interview, and secondly, criteria prioritization using a Likert scale questionnaire. As the results of EFDM, 19 criteria for green roof type selection were ranked, and categorized in four groups. Then, Decision Making Trial and Evaluation Laboratory was employed for the assessment of the causal relationships among the identified groups and criteria. It was concluded that the application of green roof is the most effective group for DM, while the cost of green roof is highly affected by other groups. Moreover, four highest influential criteria in DM for green roof type selection were discussed.