Provisional Legislative Council Panel on Housing On Ning Garden Background

Following the discussion at the Housing Panel on 15 December 1997, Members requested supplementary information on the problems in On Ning Garden. The Government's responses to specific points raised are set out below.

Solutions to the present problems


In tackling the problems caused by soil settlement, the Government advised that the grouting method should not be used. What does the Government propose as an alternative?


The Housing Department (HD) continues to repair defects caused by soil settlement in On Ning Garden following the failure of the developer to honour its 10-year undertaking on the rectification of such defects. The method and standards for repair work at On Ning Garden are the same as those used by HD in other Housing Authority estates. To alleviate owners’ concerns, HD has carried out a television survey of the underground drainage system. It will continue to monitor the condition of settlement, if any, at selected intervals at strategic locations of the estate.


As regards the structural defects, such as falling concrete, cracks in the podiums and walls and exposed steel reinforcing bars, what is the solution offered by the Government?


The owners have the right to take action against the developer if these defects prove to be latent ones. HD is prepared to mediate between the owners and the developer if both parties wish.

The Buildings Department (BD) is making preparation for inspections to establish whether detailed investigation or repair works need to be carried out under the Buildings Ordinance.


In the event that the developer, Hening Investment Limited fails to rectify the 170 identified defects which are not wholly caused by soil settlement, will the Government instruct the developer to take remedial action and undertake repair work in the same manner as it has dealt with the 96 defects caused by soil settlement?


According to the 10-year repair undertaking given by the developer, HD cannot insist that the developer rectify defects which are not wholly caused by soil settlement. HD will, however, review the causes of the remaining defects individually, and carry out the necessary rectification work if the owners are able to provide new evidence or professional justification that these defects are caused by soil settlement.

Investigation and responsibility


In his reply to the Incorporated Owners of On Ning Garden dated 18 November 1997, the Chief Executive states that BD and HD will collaborate on a further inspection and take follow-up action on the case
(Appendix I). BD also undertook to conduct a detailed investigation into the structural problems. Why has the investigation not been started? When will it commence and be completed?


As mentioned in the reply of 18.11.97 from the Private Secretary to the Chief Executive to the Incorporated Owners of On Ning Garden, BD and HD have been discussing further inspection and follow-up action. BD has not undertaken to conduct a detailed investigation into the structural problems with a view to administering repair as this is beyond its statutory functions. As mentioned in R2, BD will conduct an inspection to establish whether detailed investigation or repair works need to be carried out under the Buildings Ordinance.


Before issuing Occupation Permits (OPs), will BD officers conduct site inspections to ensure that buildings are constructed in accordance with the approved plans and the provisions of the Ordinance and regulations? If so, what were the justifications for issuing an OP for On Ning Garden which was plagued with a series of structural problems right from the time when it was completed in 1991?


Before occupation permits are issued, BD has to consider the certificates signed by authorised persons, registered structural engineers and registered contractors that the buildings have been constructed in accordance with approved plans and are structurally safe. Moreover, consideration is given to the results of the sampling tests on structural elements carried out by professionals responsible for signing the certificates and BD during construction, and the results of general site inspections conducted by BD upon receipt of the application for OPs.

There was no evidence of structural problems at On Ning Garden at the time it was completed in 1991. The above procedures were followed and no irregularities found.


According to the letter from the Incorporated Owners of On Ning Garden to CE dated 10 November 1997, a BD engineer has admitted that there was maladministration in giving approval to the project and that On Ning Garden was not constructed in accordance with the plans approved by the Building Authority (Appendix II). Is this the case? If not, can the Government provide relevant records and documents to prove that all procedures have been followed properly and no maladministration has been taken place?


The engineer from BD did not say that there had been maladministration in giving approval to the project. He did, however, point out to the Chairman of the Incorporated Owners of On Ning Garden that the concrete cover of the first floor beams in Blocks 3 & 4 might fall short of the requirement of the approved plans, and that one possible reason was inadequate site supervision by the concerned authorised person, registered structural engineer and registered contractor.

Records and documents showing compliance with the required procedures are available for inspection upon request.


Before 1993, the Director of HD was the Chairman of the Private Sector Participation Scheme (PSPS) Committee, the function of which, inter alia, was to scrutinize the approval list of developers eligible for tendering PSPS projects. In view of the crumbling state of the buildings in On Ning Garden under PSPS, does it mean that the Director of HD has failed to ensure that the developer has fulfilled its obligation in producing quality buildings and he has to bear the responsibility for the construction defects found in On Ning Garden?


Housing projects under the PSPS are undertaken by private developers. In selecting tenders, consideration is given not only to the tendered premium but also to the "non-premium" aspects of tenders which include overall planning and detailed design of projects, past performance and financial capability of tenderers, and other proposals relating to construction, environment and future management.

Concerning building inspections, the practice for PSPS projects, which is similar to that for private housing developments, is prescribed in the Buildings Ordinance. Authorised Persons and Registered Structural Engineers are required to supervise building and structural works associated with PSPS projects periodically as may be necessary, and Registered Contractors are required to supervise building works continuously. Their respective roles are to ensure that buildings constructed are in accordance with the plans approved by the Building Authority and the provisions of the Ordinance and regulations. While the Director of Housing appoints an independent surveyor to oversee the development of the project generally and to monitor progress, the project developer employs professionals to undertake, and be responsible for, the design and the construction of the project.


At the Council meeting on 3 December 1997, the Secretary for Housing said that the role of an independent surveyor appointed by the Director of Housing was to oversee the development of the project. In the case of On Ning Garden, why was the independent surveyor unable to detect the structural problems during the construction period? What exactly was his function? How did he oversee the development?


The Monitoring Surveyor (MS) was appointed by the Director of Housing as his representative to oversee the general construction progress and compliance with the Technical Schedule of the Tender Conditions of On Ning Garden. The MS was required to report on any visible building defects and any delay in the progress of construction. But the MS was not required to take over the role of the AP who was fully responsible for the supervision of construction and standard of workmanship.


At the same Council meeting, the Secretary for Planning, Environment and Lands said that HD was conducting a thorough investigation into the case of On Ning Garden. When will the investigation be completed? Will the investigation result be released to Members and the public?


HD has already undertaken the investigation to determine the extent of defects caused by soil settlement, and advised Members as well as the owners of the results.

Soil settlement


Considering the fact that there are other housing estates built on reclamation land in Tseung Kwan O, why do they not experience soil settlement problem as serious as On Ning Garden?


The ground surface of reclamation sites formed by placing of fill over soft compressible materials such as marine mud is susceptible to settlement. The effect of post-construction settlement on a project is determined by a number of factors such as the thickness of the soft, compressible layer, the type of treatment used or ground improvement made to the reclamation, the time between the completion of reclamation and completion of building works, and the design and construction details of the project. As these factors vary from site to site, settlement for some sites may be greater than in others even though they are in the same area or district.


When the Government required Hening Investment Limited to undertake rectification works of defects caused by soil settlement within a period of 10 years, was the Government well aware that there would be serious problems arising from soil settlement?


Please also refer to R10. Upon expiry of the one year Defects Liability Period (DLP) the developer continued to make good defects caused by soil settlement. To give further assurance to the owners, the developer agreed to give an undertaking to carry out repair work to all soil settlement related defects within a ten-year period from the date of issue of the Occupation Permit.


If structural problems will inevitably arise due to soil settlement in reclamation land, why are developers of other housing estates in Tseung Kwan O not required to furnish similar undertakings? Do the residents need to be protected too?


Soil settlement in reclaimed land does not necessarily give rise to structural problems as these are taken into account during the design phase. The furnishing of a 10-year repair undertaking by the developer of On Ning Garden in 1993 to HD was a good will act by the developer. Developers of PSPS developments were then under no obligation in the Conditions of Sale to give such an undertaking. Since 1995, improvement measures have been introduced to the Conditions of Sale of PSPS projects requiring developers to be liable for a list of scheduled defects such as concrete spalling, water seepage and building/soil settlement for a period of five years, apart from the one-year DLP.


Who was responsible for the site formation works for the development of On Ning Garden? Were there any procedures missing during the process of site formation works?


The site was formed by the Territory Development Department (TDD) before being handed over to the PSPS developer to carry out foundation and building work. No procedures were ommitted during site formation. The site was formed by reclamation with wick drains installed to accelerate soil consolidation during construction so as to minimise subsequent settlement. The method has been commonly used for reclamation sites including those in Tseung Kwan O and Ma On Shan.


Who was responsible for the decision on the commencement of the building works on the site? Was the Government aware at that time that there could be problems caused by soil settlement?


The authorised person and registered structural engineer acting for the developer prepared and submitted development proposals for approval and consent for commencement of building works on site by the Building Authority. The Building Authority gives approval to the applications after being satisfied that standards of structural stability and safety would be met.

The Government was aware that there would be residual settlement at the site and the developer would have to take this into account in preparing its development proposals. Accordingly, building plans were approved on the basis that the foundations would be carried down to bedrock, thereby ensuring structural stability despite any possible ground settlement.

Compensation for residents of On Ning Garden


Will the Government consider the request made by the concerned residents that they should be compensated for the expenses incurred in relation to construction defects in On Ning Garden?


As a matter of principle, it is not appropriate for Government to bear expenses arising from default by private developers or their contractors. While the owners of On Ning Garden have the right to take up any area of dispute directly with the developer, HD will do all it can to mediate in the dispute between the developer and the owners, and to help resolving the problems involved.

Liaison with the owners


Members requested that the Government should keep close liaison with the owners of On Ning Garden on repair works and provide members of the Panel on Housing with regular situation reports on the development.


HD is holding liaison meetings with the owners on a regular basis to discuss the arrangements on the repair works associated with soil settlement. HD will provide Members of the Panel on Housing with regular situation reports on the development.

Possible future improvements


How to ensure quality buildings are produced under PSPS in the future? Can housing projects under PSPS be subject to the same monitoring mechanism as that for HOS?


Please refer to R7. Since 1997, a weighted scoring system has been adopted to ensure more objective assessment of tenders submitted by developers.

PSPS projects are built by private developers. The developer and his AP are responsible for ensuring the quality of the buildings they produce.


Under the existing system, the Government relies solely on the professionals in ensuring the quality of building and structural works. However, unfortunately in many occasions, the professionals are found not reliable as in the case of On Ning Garden. So how does the Administration ensure a more effective mechanism in monitoring the professionals involved in housing projects? Will measures be put in place to ensure the credibility of the results of building inspections carried out by the developers?


Authorised persons, registered structural engineers and registered contractors are registered under the Buildings Ordinance. The Ordinance sets out conditions for registration, including the qualifications and experience of the applicants and in the case of a contractor, the experience and qualifications of its personnel, its access to plant and resources and its management structure. The Authorised Persons’ and Structural Engineers’ Registration Committee and the Contractors’ Registration Committee, comprising representatives from the industry and BD, assist the Building Authority in ensuring that the applicants for registration meet with the necessary requirements. Registered professionals and contractors are liable to both disciplinary proceedings and sanctions under the Ordinance.

This said, BD has kept under review the admission requirements into the respective registers. A new Contractors’ Registration System for general building contractors came into operation on 7.11.1997 and a new system for specialist contractors will come into operation in the second quarter of 1998.


At the council meeting on 3 December 1997, the Secretary for Housing said that the Government was undertaking a comprehensive review of its mechanism in monitoring the building quality and maintenance of housing estates under PSPS, including reviewing different roles played by different departments/officers. When will the review be completed, and will the result be made available to Members?


The Government is studying the monitoring mechanism for housing projects under the PSPS. There is no schedule for the study as it is part of our continuous effort to improve the scheme. We will inform the Panel on Housing if we decide to make any major changes to the operation of the PSPS.


A motion was passed after a discussion on "Quality of flats under subsidized home ownership schemes and the responsibility of Housing Authority" at the Panel meeting on 17 November 1997 (Appendix III). What is the response of the Government to the motion?


For projects under the PSPS, please refer to R15 and R19. For projects under the Home Ownership Scheme, the Housing Authority, as developer, is always prepared to consider suggestions of further ways to enhance the quality of its flats.

Housing Bureau
February 1998