Contents

Contents
Introduction
Section A

Building New Territories Exempted Houses under the Buildings Ordinance (Application to the New Territories) Ordinance, Chapter 121
Section B

Guidelines to Apply for Certificates of Exemption in the Construction of New Territories Exempted Houses
Section C Technical Requirements for Critical Structural Elements in the Construction of New Territories Exempted Houses
Appendices
Introduction

This pamphlet gives guidance information for indigenous villagers to build small houses. Such information is also applicable to the redevelopment of village houses in the New Territories.

The pamphlet outlines the maximum dimensions of a New Territories Exempted House and provides general guidelines on how to apply for Certificates of Exemption. It also contains technical requirements for the construction of the critical structural elements of New Territories Exempted Houses.

The pamphlet is divided into the following sections:

SECTION A : Building New Territories Exempted Houses under the Buildings Ordinance (Application to the New Territories) Ordinance, Chapter 121

SECTION B : Guidelines to apply for Certificates of Exemption in the Construction of New Territories Exempted Houses

SECTION C : Technical Requirements for Critical Structural Elements in the Construction of New Territories Exempted Houses

Any person who wishes to apply for Certificates of Exemption may obtain application forms from New Territories District Lands Offices.
Section A

Building New Territories Exempted Houses under The Buildings Ordinance (Application to the New Territories) Ordinance, Chapter 121

  1. Exemptions permitted under the Buildings Ordinance (Application to the New Territories) Ordinance, Chapter 121

    A New Territories Exempted House in the New Territories may be constructed to a height of not more than 8.23 m (27 ft.).

  1. Criteria to be observed

    1. The building may not exceed three storeys;

    2. The roofed-over area may not exceed 65.03 m2 (700 sq. ft.);

    3. The thickness of each load-bearing wall of the building :-

      1. in the case of a reinforced concrete wall shall not be less than 175 mm (6.89 in.);
      2. in the case of a brick wall of the lowest storey shall not be less than 340 mm (13.39 in.);

      3. in the case of a brick wall of any higher storey shall not be less than 225 mm (8.86 in.);

    4. The use of column and beam concrete frame construction is acceptable subject to the dimensions referred to in para. 2. c. i. and para. 4. c. of this section being complied with; and

    5. All retaining walls including any structure retaining earth or fill are considered to be site formation works not building works.

  2. Determination of the height of the building

    1. Height means the perpendicular height of the building measured from the level of its lowest point at ground level to the level of the highest point of its roof. (See Appendices I-III)

    2. In determining the highest point of a roof no account shall be taken of :-

      1. one stairhood if it has a roof area of not more than 7.44 m2 (80 sq. ft.), a height of not more than 2.14 m (7 ft.) and is erected and used solely to provide protection from rain and sun for a stairway used to gain access to the roof of the building;
      2. any parapet on the roof if the height is not more than 1.22 m (4 ft.); or

      3. one water storage tank if it has a roof area of not more than 2 m2 (21.52 sq. ft.), a height of not more than 1.22 m (4 ft.) and is installed at any point on the roof other than on a stairhood. (See Appendix I).

  3. Separation of adjoining buildings by means of party wall(s)

    Where a domestic building is divided into separate units by means of one or more party walls each such unit shall, for the purposes of this Ordinance, be considered to be a separate building if any such party wall :-

    1. where that building is of a height of not more than 7.62 m (25 ft.), is a load-bearing brick wall of not less than 225 mm (8.86 in.) thick;

    2. where that building is of a height of more than 7.62 m (25 ft.) but not more than 8.23 m (27 ft.) :-

      1. for the height of the lowest storey, is a load-bearing brick wall not less than 340 mm (13.39 in.) thick; and

      2. for subsequent floors, is a load-bearing brick wall not less than 225 mm (8.86 in.) thick; or

    3. is a load-bearing reinforced concrete wall not less than 175 mm (6.89 in.) thick.

  4. Definition of a 'Party wall'

    'Party wall' means a load-bearing wall :-

    1. forming part of a building used or constructed to be used for the purpose of separating adjoining dwellings; and

    2. which extends continuously :-

      1. from the floor level of the lowest floor of the building up to the underside of the roof; and

      2. (ii) from an external wall to the external wall opposite; and

    3. which has no door, doorway, arch, archway, window or other opening constructed in it.

  1. Certificates of Exemption

    Certificates of Exemption should be obtained from the District Lands Office prior to the commencement of any building works. These certificates relate to building works in addition to site formation and drainage works. Failure to obtain the necessary Certificates of Exemption from the District Lands Officer may mean that the building may by default come within the ambit of the Building Authority which may have no choice but to require demolition under section 24(1) of the Buildings Ordinance should structures be erected without approved plans. The District Lands Officer of a District in the New Territories is authorized by the Director of Lands to issue such Certificates.

  1. Criteria for exemption of building works

    2. Please refer to paragraph 1 and 2 of this Section for building works exemption criteria.

  2. Criteria for exemption of site formation works

    1. The maximum gradient across the lot from boundary to boundary is not more than 15 degrees;
    2. The overall gradient of an area bounded by lines 10 m (32.80 ft.) outside the lot boundary in any direction is less than 15 degrees;
    3. There is no slope within the area 10 m (32.80 ft.) outside the lot boundary steeper than 30 degrees or higher than 1.5 m (4.92 ft.); and

    4. There is no retaining wall or terrace wall either within the lot or within the area 10 m (32.80 ft.) outside the lot which is higher than 1.5 m (4.92 ft.).

  3. Criteria for exemption of drainage works

    4. Individual lot owner is urged to consult the concerned District Lands Office prior to commencement of works to ensure that drainage proposals are acceptable. Individual house lot should be relatively straightforward but groups of houses developed together will need detailed drainage proposals to be approved before a Certificate can be issued.

SECTION B

Guidelines to Apply for Certificates of Exemption in the Construction of New Territories Exempted Houses

  1. General

    1. New Territories Exempted Houses, although being relatively simple in their general arrangement and design, possess critical structural elements such as cantilevered balconies which are essential to building safety. (Critical structural elements include cantilevered balconies and canopies; long span beams (those equal to or exceeding 6m in span); long span slabs (those equal to or exceeding 4.5m in span) and foundation footings.)

    1. Any person who is given approval by a District Lands Officer to construct New Territories Exempted House (e.g. to construct a small house under the Small House Policy or to redevelop a village-type house) must apply for the issue of Certificates of Exemption pursuant to the Buildings Ordinance (Application to the New Territories) Ordinance Cap. 121 in respect of building, site formation and drainage works before commencement of the works.

    1. The Certificate of Exemption in respect of building works includes technical requirements aimed at ensuring structural safety of the completed New Territories Exempted House. The guidelines below provide information on how to apply for the Certificates of Exemption and how the construction works should be monitored and supervised.

  1. How to Apply for Certificates of Exemption

    1. With effect from 8 May 1999, District Lands Officers will only consider the issue of Certificates of Exemption in respect of building, site formation and drainage works upon receipt from an applicant of a completed application form (Form CE/1) together with two completed Letters of Appointment (Form CE/2 and Form CE/3). These Forms are obtainable from New Territories District Lands Offices.

    2. An applicant (or an individual acting under his Power of Attorney) applying for Certificates of Exemption in respect of building, site formation and drainage works shall:

      1. complete and sign Form CE/1 himself agreeing that no building, site formation and drainage works will commence prior to the granting of the Certificates of Exemption;

      2. appoint a building contractor and a *T2 competent person (or higher qualification) to construct the entire building including the critical structural elements and ask them to complete and sign the Letter of Appointment Form CE/2 and submit relevant documents to prove qualifications and experience; and

*A T2 competent person means a person who possesses a higher diploma or higher certificate in the civil/structural/building disciplines, awarded by the Technical Colleges which are approved and/or recognized by the Vocational Training Council and with a total relevant working experience of not less than 3 years.

      1. appoint a Registered Structural Engineer or a Registered Professional Engineer (specialized in civil/structural/building work) to monitor the construction of the critical structural elements and ask him to complete and sign the Letter of Appointment Form CE/3.

    1. If an applicant changes the T2 competent person or the Engineer, he should keep the District Lands Office informed in writing and submit new Letters of Appointment.

  1. Issue of Certificates of Exemption

    1. District Lands Officers will normally issue Certificate of Exemption in respect of building works upon receipt of the duly completed Form CE/1, Form CE/2 and Form CE/3. The Certificate of Exemption in respect of building works will, among other things, contain a set of technical requirements for critical structural elements in the construction of New Territories Exempted Houses. A set of technical requirements is contained in Section C of this pamphlet.

    2. Certificates of Exemption in respect of site formation and drainage works are normally issued by District Lands Officers together with the Certificate of Exemption in respect of building works. If Certificates of Exemption in respect of site formation and drainage works are not issued by the District Lands Officer due to site constraints, the applicant is required to submit site formation and drainage plans formally to the Building Authority under the terms of the Buildings Ordinance for approval. No site formation and drainage works shall commence unless relevant plans have been approved by the Building Authority.

  1. Construction of the building

    1. The T2 competent person shall supervise the building contractor in the construction of the entire building including the critical structural elements in accordance with the technical requirements as contained in the Certificate of Exemption in respect of building works.

    2. The Registered Structural Engineer or Registered Professional Engineer shall monitor the construction of the critical structural elements including the cantilevered balconies and canopies, long span beams, long span slabs and foundation footings in accordance with the technical requirements as contained in the Certificate of Exemption in respect of building works.

    3. The respective responsibility of the T2 competent person and the Registered Structural Engineer/Registered Professional Engineer is shown on the Activity List at Appendix IV.

  2. Completion of building works

    1. Upon completion of building works, the T2 competent person and the Registered Structural Engineer/Registered Professional Engineer shall jointly certify and submit to the District Lands Officer a construction completion report (Form CE/4).

    2. In the construction completion report, the T2 competent person shall declare that he has supervised the construction of the entire building including the critical structural elements and he is satisfied that they are constructed in accordance with the technical requirements.

    3. In the construction completion report, the Registered Structural Engineer/Registered Professional Engineer shall declare that he has monitored the construction of the critical structural elements of the building and he is satisfied that all the technical requirements have been met. In addition, he shall also certify that the as-constructed critical structural elements are structurally safe.

    4. District Lands Officers will issue certificate of compliance (or letter of no objection to occupy) upon receipt of the construction completion report and at the same time upon his satisfaction that all other obligations imposed on the applicant have been fully complied with.

  1. Buildings without critical structural elements

    1. Construction of a New Territories Exempted House without any critical structural elements does not require monitoring by Registered Structural Engineer or Registered Professional Engineer so long as the foundation for the New Territories Exempted House is of a raft type construction with 375mm minimum structural thickness and 0.85% minimum steel of the cross sectional area of the structural concrete in either face and in either direction and the cover to outermost reinforcement bars not less than 40mm, nor greater than 50mm. However, supervision by a T2 competent person for the construction of the entire building is still required and he should sign a construction completion report (Form CE/5) upon the completion of the entire building.

    1. Retrospective issue of Certificates of Exemption will not be considered in respect of building, site formation and drainage works of a New Territories Exempted House constructed without first obtaining Certificates of Exemption in compliance with the new guidelines and the technical requirements. Any New Territories Exempted House constructed without a Certificate of Exemption in respect of building works shall be subject to enforcement actions.

SECTION C

Technical Requirements For Critical Structural Elements in the Construction of New Territories Exempted Houses

  1. General

    1. New Territories Exempted Houses are now conventionally constructed of reinforced concrete with shallow footings. Critical structural elements include cantilevered balconies and canopies; long span beams (those equal to or exceeding 6m in span); long span slabs (those equal to or exceeding 4.5m in span) and foundation footings.

    2. Professional advice should be sought if non-conventional building materials are used, e.g. structural steel; or when deep foundation are involved; or when the foundation are constructed in the vicinity of a slope or a retaining wall; or in case of doubt in complying with these Technical Requirements.

  2. Construction Materials

    1. Concrete used should be not inferior to grade 25D as specified in Building (Construction) Regulation, i.e. with a minimum crushing strength of concrete of not less than 25MPa. Where access and availability can be arranged, the use of ready-mix concrete from suppliers certified under the Hong Kong Quality Assurance Agency (HKQAA) is encouraged for the building structure.

    2. Steel reinforcement bars used should not be inferior to grade 250 and grade 460 specified in Construction Standard CS2 for plain round bars and deformed high yield bars respectively, i.e. with a minimum yield stress of steel bars of 250MPa and 460MPa respectively.

  3. Material Testing

    1. Two numbers of standard concrete cubes should be prepared and tested in accordance with the requirements of Construction Standard CS1 when constructing each one of the following parts of the structure : foundation; vertical members for each floor and horizontal members for each floor. The tests should be carried out by a laboratory accredited with the Hong Kong Laboratory Accreditation Scheme (HOKLAS).

    2. All steel reinforcing bars used should possess a manufacturer𠏋 certificate indicating that the requirements given in Construction Standard CS2 with respect to the physical, chemical and mechanical properties of the steel bars have been complied with.

  4. Balconies and Canopies

    1. Structural Design

      1. For balconies and canopies with cantilevered projections of span more than 1000mm, a beam-and-slab type construction should be used instead of cantilevered slab type of construction, where practicable. For beam and slab construction, slabs must be fully supported by beams at all sides and the overall depth of any cantilevered beam should be not less than 300mm at support. For cantilevered slab projections, the span to overall structural thickness ratio should be not greater than 7 and the structural slab thickness should be not less than 150mm. The concrete cover to the outermost reinforcement bar should be not less than 40mm, nor more than 50mm.

      2. Cantilevered concrete slabs should be reinforced in both faces and in both directions. Reinforcement bars should be at least 10mm in diameter and the spacing should be not greater than 150mm. The main reinforcement bars in the upper and lower sides of a slab respectively should be not less than 0.25% and 0.15% of the cross-sectional area of the structural concrete. Distribution steel should be not less than half of the main steel in cross-section.

      3. Main reinforcement bars of the projecting structure should be rigidly fixed to the reinforcement of the supporting member. The reinforcement bars should extend straightly into the far face of the supporting beam before bending, if bending is required to achieve adequate anchorage. Typical details of fixing of steel bars are given in Appendices V and VI for reference.

      4. Embedded service pipes and conduits are not permitted in beams. Such embedments are also to be avoided in slabs if possible. If it is impracticable to do so, they should be arranged to run perpendicular to the supporting member.

      5. Adequate allowance must be made for the superimposed loads due to the screeding, waterproofing materials, heavy parapets, maintenance work and possible ponding resulting from malfunctioning of the drainage system. A table on the minimum required thickness of cantilevered slab balconies and canopies is given in Appendix VII for reference.

    2. Drainage Arrangement

      1. Effective waterproofing should be provided on the top surface.

      2. A fall should be laid from the supporting edge towards the outer edge to prevent accumulation of water. The minimum fall should be 1:75.

      3. Adequate drainage outlets/down pipes should be provided near the outer edge. The maximum distance between the drainage outlets/down pipes should be not more than 5 metres.

  5. Long-span Beams

    1. Structural Design

      1. Long-span beams should have supports on both ends. Span length is taken to be the distance between the centres of the supports or clear distance between the supports plus the depth of the beam whichever is less.

      2. Beam width should be not less than 300mm. The length of unrestrained compression zone of the beam should not exceed 30 times of the beam width.

      3. Beam depth should be not less than 450mm. The span to depth ratio should be not greater than 15.

      4. The concrete cover to the outermost reinforcement bars in the beams should be not less than 30mm, nor more than 50mm.

  6. Long-span Slabs

    1. Structural Design

      1. Long-span slabs should have supports at least on two opposite ends. Span length is taken to be the distance between the centres of the supports or clear distance between the supports plus the depth of the slab whichever is less.

      2. Slab thickness should be not less than 150mm. The span to depth ratio should be not greater than 30.

      3. The concrete cover to the outermost reinforcement bars in the slabs should be not less than 20mm, nor more than 30mm.

  7. Raft or Strip or Pad Footings

    1. Structural Design

      1. All columns should be supported by footings and be connected by a rectangular grid of strap beams at the support end.

      2. A minimum of two trial pits should be carried out to determine the condition of the subsoil and the allowable bearing pressure. Footings must not sit on top soil, loose fill, abandoned foundation or debris.

      3. Footings should be founded at least 1m below ground surface unless solid rock is encountered.

      4. Raft footings are generally preferred to single pad footings or strip footings. Raft footings should be adopted when the subsoil is medium dense to loose granular soils (which is readily removable by shovelling only) or where there is a high ground water table.

      5. Only when the subsoil is compact granular soils (which requires the use of a pick for removal) in dry condition, may single pad footings or strip footings be used.

      6. All strap beams, pad footings or strip footings should be not less than 450mm thick. Details of some typical foundation elements are shown in Appendix VIII for reference.

      7. Raft footings should be not less than 375mm thick.

      8. Pad footings should be reinforced at the lower side in both directions. The steel bars provided in either direction should be not less than 1.0% of the cross sectional area of the structural concrete.

      9. Strip footings and strap beams should be reinforced longitudinally at both the upper and lower sides. The steel bars provided on either face should be not less than 1.5% of the cross sectional area of the structural concrete and should be binded by stirrups spaced at not more than 0.75 times the overall depth of the footing or beam.

      10. Raft footings should be reinforced in both faces and in both directions. The steel bars provided in either face and in either direction should be not less than 0.85% of the cross sectional area of the structural concrete.

      11. Concrete cover to the outermost reinforcement bars should be not less than 40mm, nor greater than 50mm.

  8. Construction and Workmanship

    1. All cantilevered balconies and canopies should be cast at the same time and monolithically with the members from which they derive support. If construction joints are unavoidable, they must be located at not less than 300mm from the supporting members and be free of loose material and dirt before casting. A typical detail of construction joint is shown in Appendix VII for reference.

    2. Adequate bar spacers should be provided to maintain the position and alignment of the steel reinforcement. They should be placed at not more than 150mm from any edge of the structural element to be concreted and the spacing of all intermediate spacers should not exceed 1m.

    3. During concreting, adequate compaction should be given to ensure good quality concrete. Every endeavour should also be made to avoid steel reinforcement bars from being displaced or depressed.

    4. All proppings to the soffit of the formwork for the balconies and canopies should be maintained for at least 14 days.

    5. Excavation should always be maintained in a dry condition. A 75mm thick blinding layer of lean concrete should be laid on top of the subsoil before constructing the footings.

Enquiries

For general enquiries, please call:

District Lands Office/North

District Lands Office/Sai Kung

District Lands Office/Sha Tin

District Lands Office/Tai Po

District Lands Office/Tsuen Wan

District Lands Office/Kwai Tsing

District Lands Office/Tuen Mun

District Lands Office/Yuen Long

District Lands Office/Islands
2675 1502

2791 7019

2684 1100

2654 1263

2402 1164

2402 1164

2451 1176

2443 3575

2852 4265
Appendix I

Appendix I

Appendix II

Appendix II

Appendix III

Appendix III

Appendix IV

Activity List Showing the Respective Responsibility of T2 Competent Person and RSE/RPE in Constructing the Critical Structural Elements

General
T2
RSE/RPE

Preparation of test cubes
*

Certifying steel used corresponds with manufacturer's certificate
*

Examination of test cube results and manufacturer's certificate for steel
*
*

Foundation
T2
RSE/RPE

Inspect trial pit for condition of subsoil to determine foundation type
*
*

Prior to concreting of foundation, check structural dimensions of foundation; and adequacy, details and cover of steel reinforcement bars
*
*

Supervise concreting of foundation
*

Superstructure - cantilevered balcony/canopy
T2
RSE/RPE

Prior to concreting, check dimensions; adequacy, details and cover of steel; construction joint; and embedded service pipes and conduits
*
*

Check propping of formwork
*

Check drainage arrangement
*

Supervise concreting
*
*

Superstructure - long span beams/slabs
T2
RSE/RPE

Prior to concreting, check structural dimensions; and adequacy, details and cover of steel
*
*

Supervise concreting
*
Appendix V

Appendix V

Appendix VI

Appendix VI

Appendix VII

Appendix VII

Appendix VIII

Appendix VIII