Blog post # 2 (annotated bibliography)

Bianchini, F., & Heage, K. (2012). Probabilistic social cost-benefit analysis for green roofs: A lifecycle approach. Building and Environment 58 (2012) 152-162. Retrieved from https://doi.org/10.1016/j.buildenv.2012.07.005.

This article explains the costs of installing and maintaining different types of green roofs and its long term and social benefits. A simple extensive roof which has no public access would cost significantly lesser than an intensive green roof which has public access. “Intensive roofs are associated with roof gardens; need a reasonable depth of soil and require constant maintenance. Extensive roofs have a relatively thin layer of soil, and are designed to be virtually self-sustaining, therefore require low maintenance.”. Although green roof cost significantly higher, it would offset the cost by saving on utility costs and rainwater management and has a longer lifespan compared with conventional roofing materials. The maintenance regime consists of ‘fertilisation, irrigation, weed control, and replanting when required’.

Bianchini and Heage (2012), claimed that researchers conducted a lifespan cost on green roofs, cool roofs and conventional roofs. They concluded that while green roofs are expensive, it does provide significantly higher relative benefits over a 50-year lifecycle in terms of energy cost savings, reducing emissions, reducing stormwater fees. Compared to conventional roofs and cool roofs, green roofs provide more significant benefits in the long run. This article is comprehensive for those wanting to explore the cost of green roofs on new buildings. However, for those who wish to retrofit green roof on existing structures, i.e. which are above thirty years, would it still be cost-effective is a question to ponder. As to reap the benefit of a green roof requires long term whereas older existing buildings could post an indefinite payback period.

Commented on Jordan, Alfian and Nurul on 31 March 2019.