LCQ22: Green roof projects

Following is a question by Dr Hon Elizabeth Quat and a written reply by the Secretary for Development, Mr Paul Chan, in the Legislative Council today (June 3):


It has been reported that incorporating greening elements (e.g. green roofs) in buildings has become the major trend of environmental protection. Apart from beautifying the environment, green roofs can also help reduce the urban heat island effect and enhance the thermal insulation capability of buildings. Hence, quite a number of countries and places, such as Germany, Japan and Shanghai, are now making great efforts to promote green roofs. However, Hong Kong's performance is lagging far behind in this regard. Moreover, it has been reported that the roof greening projects implemented for government buildings by the Architectural Services Department (ArchSD) are ineffectual. For instance, the green coverage in some of the sites where roof greening projects have been completed is extremely low, with only a small quantity of potted plants or small parcels of turfed areas being grown, which does not conform to the relevant standards and requirements set by the Development Bureau in 2012. However, the ArchSD has responded that it is difficult to quantify the effectiveness of the projects concerned. In this connection, will the Government inform this Council:

(1) of the number of sites where roof greening projects of government buildings were implemented and the total size of greened areas provided, in the past three years;

(2) of the criteria or guidelines currently based on which the authorities assess the effectiveness of roof greening projects, and whether they have made references to overseas experience regularly to update such criteria or guidelines;

(3) of the mechanism for monitoring the benefits of roof greening projects so as to prevent the greened areas to be provided by the projects from being too small;

(4) whether it assessed in the past three years the number of government buildings or school premises suitable for implementing roof greening projects; if it did, of the assessment results; among these government buildings or school premises, of the respective numbers of those in which such projects (i) have been completed, (ii) will be completed/implemented, and (iii) have not been planned; whether it will commence roof greening projects expeditiously in buildings which are found suitable for but have not yet proceeded with the implementation of such projects so as to popularise green building;

(5) given that at present, roof greening projects in Hong Kong are mostly implemented in government buildings as well as primary and secondary school premises, whether the authorities will consider providing financial assistance to property owners of private buildings to carry out such projects; if they will, of the details; if not, the reasons for that;

(6) whether it will consider requiring roof greening projects to be carried out in new buildings or stipulating that a certain percentage of green roofs is required to be provided in new buildings to enhance the greening awareness of property owners; if it will, of the details; if not, the reasons for that;

(7) as it has been reported that the guidelines on roof greening currently provided by the Government to schools are very brief, whether the authorities will expeditiously formulate a set of detailed guidelines to help schools implement such environmental protection measure; and

(8) as some teachers have pointed out that schools encounter quite a number of difficulties at present in applying for the implementation of roof greening projects and the relevant financial assistance, e.g. the complicated procedures for vetting and approval of applications as well as the requirement for submission of greening project plans, and that the involvement of a number of government departments in such vetting and approval procedures has given rise to administrative confusion and unclear division of powers and responsibilities, thereby deterring a number of schools from making such applications, how the authorities will help schools and other applicants tackle the problems concerned; whether the authorities will pool resources from relevant government departments, as well as set up a green building information centre or a dedicated department to coordinate the vetting and approval of applications for roof greening projects and streamline the application procedures?



(1) The Architectural Services Department (ArchSD) has completed over 50 roof greening projects with total greened areas of over 50 000 square metres over the past three years, from January 1, 2012 to December 31, 2014.

(2) and (3) In compiling the technical circular on the standards and requirements on greenery coverage, the Development Bureau has made reference to overseas experience and standards as well as the contents and recommendations of the Council for Sustainable Development's Report on the Building Design to Foster a Quality and Sustainable Built Environment and the ArchSD's study on Green Roof Application in Hong Kong.

All new government building projects undertaken by government departments, including the ArchSD, must comply with the standards and requirements on site coverage of greenery for government building projects as set out in the Technical Circular (Works) No. 3/2012 of the Development Bureau. In other words, the greenery coverage must reach 30 per cent for a site of 20 000 square metres or more in area, and 20 per cent for a site of less than 20 000 square metres. The ArchSD will comply with the above standards and requirements for greenery coverage as set out in the Technical Circular.

(4) The ArchSD has provided greening facilities for all new government building projects, including roof greening, in accordance with the Technical Circular (Works) No. 3/2012. For existing government buildings under its maintenance purview, the ArchSD has encouraged management departments of these buildings to consider roof greening works, where conditions permit, when planning major renovation works.

The ArchSD will assess the suitability of roof greening works for buildings. Between January 1, 2012 and December 31, 2014, it has completed over 50 roof greening projects with total greened areas of over 50 000 square metres. Currently, over 25 roof greening projects with total greened areas over 16 000 square metres are underway/under planning.

(5) Based on resources consideration, the Government has no plan to provide subsidy for roof greening works undertaken by property owners.

(6) To foster a quality and sustainable built environment in Hong Kong, the Buildings Department (BD) has implemented a package of measures since April 2011. One of these measures is, where applicable, to comply with the Sustainable Building Design Guidelines (SBD Guidelines) as promulgated in the Practice Notes for Authorised Persons, Registered Structural Engineers and Registered Geotechnical Engineers APP-152 when granting gross floor area concessions for new private development projects.

For the purpose of enhancing the environmental quality of the urban space, particularly at the pedestrian level and to mitigate the heat island effect, the SBD Guidelines require new building developments with site areas of 1 000 square metres to 20 000 square metres and more than 20 000 square metres to have minimum site coverage of greenery of 20 per cent and 30 per cent respectively. The greenery areas can be provided at pedestrian zone, communal podium roof/flat roof/main roof, slope or retaining structure.

(7) The Government is committed to promoting roof greening to schools and the general public. To help schools implement roof greening projects, it has provided detailed guidelines and information, including:

* a bilingual Pictorial Guide to Plant Resources for Skyrise Greenery in Hong Kong (the Pictorial Guide) compiled by the Development Bureau to facilitate proper plant selection and encourage the use of suitable plants for skyrise greenery. This Pictorial Guide provides detailed information on the technical aspects and growth conditions of over 100 types of plants that have been successfully used in skyrise greenery projects in Hong Kong to help the schools and designers to select suitable plants for their skyrise greenery projects. A new search engine for skyrise greenery plants is also available for identifying plants suitable for the planting environment of schools. Apart from publishing the information on the Greening website (, the Development Bureau has distributed printed copies to schools and public libraries for the public's information;

* the Greening website of the Development Bureau that provides detailed information on the application of green roof at schools, including the factors for consideration, design approaches, successful examples of roof greening projects and sharing of experience of implementing roof greening at schools. For details, please visit the following site: ;

* seminars organised by the Development Bureau for schools to explain in detail the application of green roof, design considerations as well as other useful information in order to promote roof greening to schools and the general public; and

* the Development Bureau assisted the Hong Kong Green Building Council in compiling the Hong Kong Green School Guide. The section on Green Roof sets out relevant issues for consideration of schools and provides detailed and comprehensive guidelines for schools to go green step by step.

(8) Pursuant to the Buildings Ordinance (Chapter 123) (BO), the BD is required to process the building plan submissions involving green roof in accordance with the provisions of the BO and its subsidiary regulations. Moreover, under the centralised processing system, the BD would refer the plans to relevant government departments for consideration on matters in their respective areas of concern or purview. If the plans comply with the provisions of the BO and its subsidiary regulations, the BD is required to give approval of the plans under the BO. Contrarily, the BD is also required to refuse to give approval of the plans under section 16 of the BO.

The purpose of the centralised processing system for building plans is to ensure that all interested government departments are consulted and that their comments on private development proposals are collated by the BD within time limits allowed for processing building plans. For all comments relating to matters not governed by the BO, the applicants and their appointed building professionals may approach the relevant government departments direct to resolve the problem.

Ends/Wednesday, June 3, 2015
Issued at HKT 16:14