9 July 2016
Joint Statement on Rooftop Landscape (Green Roof) of Hong Kong
It is well established globally that landscaped roofs in the urban environment have multiple benefits towards a sustainable city. They are important to the enhancement of our built-environment and contribution to the amenity and recreational, environmental and ecological values, the well-being of people, and also economic and food production. The construction professionals of Hong Kong have for the last three decades made significant contribution to the advancement of landscaped roof design and construction with successful examples of completed projects that are renowned locally and internationally. The collapse of a roof at City University of Hong Kong earlier this year reveals the need to strengthen public awareness on the factors involved in the design and implementation of landscaped roofs and the importance of having adequate professional supervision throughout the process.
Landscaped roofs are technically speaking landscaped spaces integrated with built-structures. In the case of a building, it can be in the form of a podium deck, an intermediate level ‘sky-garden’, or the top level landscaped roofs. The vegetated areas of a landscaped roof can be ‘extensive’, having shallower soil depth but limited plant species options, or ‘intensive’, having deeper soil depth that allows more plant options. Different design options will require different capital costs, design considerations, technical and maintenance requirements. Rooftop landscape, whether on new or existing buildings, requires professional input on its design and technical feasibility. It is essential to engage relevant construction professionals to ensure the proposed landscape works are technically feasible, safe, lawful, and cost effective.
Architects, landscape architects, structural engineers, and surveyors are the major professionals responsible for the design and implementation of rooftop landscape. Each profession has its areas of expertise and professional accountability. For example, an authorized person under the Buildings Ordinance (who may be an architect, engineer, or surveyor) coordinates building works and ensures that they are in compliance with the Buildings Ordinance and its subsidiary legislations; the structural engineer evaluates structural feasibility and provides structural design to the proposed landscape works; the landscape architect designs and provides specifications for the soft and hard landscape systems. Same as other construction works, it usually requires a team effort from these professionals to ensure the safety, viability, legality, quality, and cost effective of the proposed landscaped roofs.
Particular to a compact city like Hong Kong, the multiple benefits of landscaped roofs (or green roofs) in enhancing the living environment are widely recognized. In order to promote sustainable development of our city, we will continue to offer our support and professionalism to the government and the general public in areas such as education and raising public awareness, review and enhancement of existing guidelines, as well as strengthening of the existing statutory controlling framework.
The Hong Kong Institute of Architects
The Hong Kong Institution of Engineers
The Hong Kong Institute of Landscape Architects
The Hong Kong Institute of Planners
The Hong Kong Institute of Surveyors
Please click HERE to download a copy of the above joint statement.