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LCQ14: Implementation of green roof projects for government buildings

     Following is a question by the Hon Lau Kong-wah and a written reply by the Secretary for Development, Mrs Carrie Lam, in the Legislative Council today (November 14):


     It has been reported that green buildings have become very prevalent in recent years.  Recently, I have also received requests from some residents of the Sha Tin District for greening the rooftops of the Sha Tin Town Hall and the Sha Tin Public Library.  They pointed out that greening rooftops could beautify the environment on the one hand and provide more leisure open space on the other.  Furthermore, they can help lower the room temperature in the buildings concerned, reduce energy consumption and promote environmental protection.  The Government once said that the Architectural Services Department (ASD) would implement green roof projects for new government buildings as far as practicable since 2001. In this connection, will the Government inform this Council:

(a) of the number of green roof projects implemented for government buildings in Hong Kong since 2001; of the number of such projects to be carried out in the next three years;

(b) of the percentage of the number of government buildings for which green roof projects have been implemented in the total number of government buildings in Hong Kong at present; whether ASD will explore the possibility of adding green features to the rooftops of all existing government buildings, so as to benefit more people; and

(c) in order to attenuate the urban heat island effect, whether the authorities will consider including roof greening in the standard construction specifications for new government buildings, in particular cultural and recreational facilities, so as to make an extra effort for the cause of environmental protection?



Hong Kong is a densely populated place.  To beautify the environment and attenuate the heat island effect, the Government has been actively promoting greening in recent years.  In view of the limited space available for planting in the urban areas, we have been proactively promoting innovative greening techniques, such as roof greening, to enhance the urban environment.

My reply to the three parts of the question is as follows:

(a) From 2001 onwards, the Architectural Services Department (ASD) has, where practicable, incorporated roof greening in the design of new buildings if there is adequate usable rooftop space, after taking into account the actual conditions (such as the rooftop loading capacity, structural safety, the drainage and irrigation arrangements, and the building height).  Starting from 2006, the ASD has further encouraged departments which manage existing government buildings to incorporate roof greening works into their roof refurbishment projects if the building structure, availability of rooftop space and waterproof design etc. so permit.  Other works departments have also implemented roof greening works, where practicable, in appropriate building projects.  As at end October 2010, a total of 159 government buildings maintained by the works departments had green roofs.  In addition, the works departments are currently undertaking roof greening works at 62 government buildings (including new buildings and buildings under refurbishment).  Planning and design of roof greening works for another 32 government buildings are underway for implementation within the next three years.

(b) At present, the works departments are responsible for the maintenance of some 8,500 government buildings.  New buildings completed in recent years account for only a small proportion, while most buildings are at least 10 years old.  About 159 of these buildings (about 2%) have green roofs.  For buildings already in existence, if they require any roof refurbishment works in future, the departments concerned will consider carrying out roof greening works under the established policy, taking into account the actual circumstances and technical feasibility.

(c) As explained above, it is the current practice of the works departments concerned (e.g. ASD, Drainage Services Department and Water Supplies Department) to proactively consider incorporating roof greening features into building projects under their purview.  Notwithstanding, it would be difficult to impose a mandatory requirement on all building projects to install green roofs since there may be practical and technical constraints from some of the projects.  To further promote roof greening in government and private building projects, the Greening and Landscape Office (GLO) under the Development Bureau coordinates with the departments concerned in conducting research on roof greening techniques (e.g. suitable plant species and plant growth medium) and disseminating the research findings.  The GLO also organises professional seminars to promote these techniques to the landscaping sector, professionals and government officers, with a view to promoting roof greening technologies by lowering the technical thresholds.

Ends/Wednesday, November 10, 2010
Issued at HKT 16:18


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