Financial viability of using green roofing in residential buildings

Abstract

As a result of increased attention towards sustainability worldwide, green concepts have become popular in the construction industry. Green roof is one of the essential elements in a green building that provide many advantages while creating a pleasant appearance for the total building. Green roofs play a major role in energy saving of a building. However, compared to a conventional roof, the initial and maintenance costs of a green roof is quite high due to the additional construction and high maintenance requirements. Thus, this paper compares the Life Cycle Cost (LCC) of a green roof with that of a conventional ceramic tile roof in order to determine the financial viability of green roofing. Findings were gathered from several cases and past researches under initial cost, maintenance cost and energy saving of green roofs and adopted to the selected case for the analysis. Findings of the study indicate that initial cost of the green roof was higher than conventional and represented 8.39:(-6.55) proportion of the total life cycle cost of the building. Similarly, maintenance, operational and replacement costs were also higher than the conventional representing 12.08:(-6.55) proportion of the total life cycle cost of the building. Green roof also had higher energy cost than the conventional, representing (-23.64):(-6.55) proportion of total life cycle cost of the building. As a result, it was found that (-Rs. 11,654.70)/m2 net saving by a green roof is considerable despite of the high initial and the maintenance cost. According to the study, green roofing concept is financially and environmentally beneficial concept even though there are some barriers, like lack of knowledge, lack of techniques, lack of standards in implementing this concept in the Sri Lankan context. Hence, it is recommended to use green roofing in residential buildings.