I recently completed a literature review on green roofs. I concluded that an extensive green roof is 2{e3829ec1db02d54faaf9fa2de0d48db26af01d7a7944a63c3b26976124791cab} cost increase over 40 years. Standard roof membranes are expensive to replace and have a life span of around 20 years. So in the long term- the additional cost is negligible. The issue of developer/ builder and owner is where the cost gets more complicated. There are international examples where govt offer incentives to mitigate the initial cost burden.
Nina,
Thanks so much for sharing the results of your study!
I completely agree with you that the main hurdle is the developer with discussing upfront costs. Here in China, developers often build with short-term horizons (often selling their properties within 5 years) thus making the implementation of some sustainable strategies harder to realize.
Our project in Hong Kong however, the Rosedale Hotel Kowloon, is a great success story. The developer (new to LEED at the time) took a leap of faith and decided to incorporate an extensive green roof system throughout most of the roof and balcony spaces in the property. The Rosedale is now the ONLY building in that area of Hong Kong to have such a system and guests are LOVING IT…not to mention is just obtained a high LEED Gold rating!
Best,
Alex
