Waterproof membrane

Garden roofs, sometimes known as green roofs or rooftop gardens, are specialized roof systems that support vegetation growth. With technical advances in roofing materials and components, garden roof systems can now be successfully installed in most climates, providing an attractive design option, especially in urban areas where land available for parks and green space is limited. As well, concern about sustainability and climate change have led to increased interest in garden roofs as a possible means of helping address these issues. However, while garden roofs are increasing in popularity, there is little infor-mation on their performance in cold climates. What Constitutes a Garden Roof? Garden roofs, which can be installed on both conventional and protected-membrane roofing systems (see Figures 1 and 2), require additional components, such as a root-resistant layer, a drainage layer, a filter membrane and a growing medium, to support the growth of vegetation. Typical components and their functions are summarized in Table 1. Garden roofs are gener-ally considered to be “intensive” or “extensive, ” based on the weight of the system (Table 2). By K.Y. Liu and A. Baskaran There is increasing interest in the garden roof system as a sustainable building design option in North America today. This Update reports the results of a field study to evaluate the thermal performance of this technology, as well as its potential to retain storm water runoff