Vertical greening works

15/6/2016

 

Following is a question by the Professor Hon Joseph Lee and a written reply by the Secretary for Development, Mr Paul Chan, in the Legislative Council today (June 15):

Question:

     On the 20th of last month, the entire greened roof of the Chan Tai Ho Multi-purpose Hall at the City University of Hong Kong collapsed abruptly, and it has been reported that this accident is attributable to the greening works on the roof of the building. Some members of the public have pointed out that, apart from roof greening works, vertical greening works on the external walls of buildings may also pose safety hazards to the public. In this connection, will the Government inform this Council:

(1) whether it knows the current number of buildings in Hong Kong on which vertical greening works have been carried out; and how the authorities regulate such works;

(2) of the measures to ensure the structural safety of buildings on which vertical greening facilities/installations have been retrofitted; whether the authorities inspect on a regular basis the safety of the relevant works and facilities/installations; if they do, of the details; if not, the reasons for that; and

(3) whether the authorities will comprehensively review the current regulatory arrangements for vertical greening facilities/installations; if they will, of the details; if not, the reasons for that?

Reply:

President,

     Greening of buildings can bring many benefits in terms of improving the environment and the ecology, saving energy, as well as enhancing people's quality of living. Vertical greening, being one form of greening of buildings, usually refers to planting of climbing or weeping plants along the edges of buildings, or planting on stacks of modular planters or panels and aims at creating greenery on the vertical surface of associated structures. Vertical greening can enhance a building's energy efficiency by serving as its thermal insulation, mitigate urban heat island effect by moderating temperatures and humidity, as well as filter dust pollutants and reduce noise. In view of all these benefits, the Government has been striving to promote greening of buildings, including vertical greening.

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

(1) With the paramount objective of ensuring building safety, the Government has in place different levels of regulatory control over the greening of private buildings, including vertical greening. If the greening is of a substantial scale, the relevant owner should then consult authorised building professionals on matters such as loading of the building. The building professionals authorised by the Buildings Department possess professional expertise. They should advise the owners, where the greening involves building works, on the need for seeking the consent of the Buildings Department for the works taking into account their location, scope and scale. For works requiring its prior approval, the department will assess the works proposed in accordance with the Buildings Ordinance and will only give consent for its commencement upon being satisfied of the safety of the works. As regards statistics, the Buildings Department does not have the number of private buildings in Hong Kong on which vertical greening works have been carried out.

(2) and (3) Owners of private buildings are responsible for the timely inspection and maintenance of their properties, including any of their greening facility, to ensure their safety. They should consult professional advice if in doubt. Relevant departments have formulated guidelines on the pertinent matters to assist the owners in fulfilling their responsibilities. In particular, the Development Bureau has been formulating standards and guidelines on various types of greening since the establishment of its Greening, Landscape and Tree Management Section in 2010. In view of the collapse incident of the greened roof at the City University of Hong Kong last month, the Buildings Department has issued a circular to the building industry, setting out and reminding practitioners of the existing provisions under the Buildings Ordinance applicable to roof greening. These provisions equally apply to vertical greening. The circular particularly reminds the relevant professionals and contractors of their duties to inform building owners of the actions to be taken during the design and construction of the greening facilities, the impact of greening on the structure of the subject building, and how to safely operate and properly maintain the relevant facilities after commissioning. To enhance public knowledge of the relevant subject, the Buildings Department is drawing up a guide for property owners and the general public on the common greening works of buildings in Hong Kong.

     The Buildings Department has not carried out inspections of the vertical greening of buildings specifically. In its day-to-day handling of public reports on unauthorised building works and other matters, as well as in conducting large-scale operation, the Buildings Department will take appropriate follow-up actions if any greening facilities which are unauthorised building works come to its attention.

     Generally speaking, just as other forms of greening, vertical greening of buildings should pose no risk to safety, as long as it was suitably designed and constructed, and there are proper repairs and maintenance. As such, we have no plan at present to comprehensively review the relevant regulatory arrangements.

 

 
Last Updated 2016-06-15