Productive Green Roofs

Abstract

Although interest in productive gardening, as part of a healthy, high density city lifestyle, is growing rapidly, severe spatial constraints limit opportunities for ground-level community gardens and urban farms. Over the last ten years, community groups in cities around the world have begun to activate under-utilized building roof spaces for use as community-based urban rooftop farms (URF). These spontaneous projects offer valuable opportunities to address this situation by creating city-based venues for food production, social interaction, and active recreation, and have generated a sense of stewardship for the built environment. Additionally, URFs can have environmental and sustainable building benefits, such as improved building thermal performance, reduced urban heat island effect, increased sound insulation, and urban greening, similar to those of traditional green roofs systems. This paper reports on an on-going research study to determine the potential for URFs in Hong Kong. All existing URF projects within the Territory were surveyed, to determine the building, environmental, operational and community conditions under which they occur. Analysis of building and land use across all urban districts revealed that some 594ha of existing roof space may be suitable for farming. Assessment of participation rates in open-to-public farms indicate that URFs could provide opportunities for active participation to more than 18,000 people. Given that existing farms are entirely community driven and receive no policy, technical or financial support from Government, potential participation could be much higher. This suggests considerable positive environmental and social benefits could be achieved at the city-scale if URFs were actively promoted and formally incorporated into urban land use planning and city decision making processes. Keywords: Urban Rooftop Farming; Community Empowerment; Healthy Urban Lifestyle