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Introduction to Minor Works Control System

Household Minor Works Validation Scheme

Inspection and Certification of Prescribed Building or Building Works (also known as "Household Minor Works Validation Scheme")

The Household Minor Works Validation Scheme (HMWVS) is established under the MWCS to facilitate members of the public to retain, after validation, minor household installations including air-conditioner supporting frames, drying racks and small canopies constructed without the prior approval of plans from the Buildings Department before the full implementation of the MWCS.

The following four items are prescribed building or building works under the HMWVS:

Household Minor Works Validation Scheme (HMWVS)
Item The prescribed building or building works
1. Unauthorised supporting structure for an air-conditioning unit, water cooling tower or any associated air duct
  • On-grade or on a slab (not cantilevered)
  • Weight of the cooling plant ≤ 100kg
2. Unauthorised metal supporting frame for an air-conditioning unit or any associated duct
  • Projection ≤ 600mm
  • Weight of the cooling plant ≤ 100kg
  • No projection over street or common part of building if the highest point of frame ≤ 3m from ground
3. Unauthorised drying rack
  • Projection ≤ 750mm
  • No projection over street or common part of building if the highest point of rack ≤ 3m from ground
4. Unauthorised canopy
  • Projection ≤ 500mm
  • No concrete
  • No projection over street or common part of building if the highest point of canopy ≤ 3m from ground

The appointed person should be one of the following person:

The appointed person
The Appointed Person for Inspection
Prescribed Building Professionals (PBP)
  • Authorized Person (AP)
  • Registered Structural Engineer (RSE)
  • Registered Inspector (RI)
Prescribed Registered Contractor (PRC)
  • Registered General Building Contractor (RGBC)
  • Registered Minor Works Contractor (RMWC(Co))
    1. Type A minor works (i.e. addition & alteration works) or
    2. Type E minor works (i.e. works relating to structures for amenities)
  • Registered Minor Works Contractor (RMWC(Ind)) registered for items 3.25, 3.27, 3.28, 3.29, 3.34, 3.35, 3.36, 3.37 & 3.38

Flow Chart for the validation of household minor works

The person who arranged for the validation of minor household installations

Appoint PBP OR Appoint PRC

PBP/ PRC to carry out the inspection and certification of the household installations to ensure that the safety requirements and the respective specifications of the prescribed building or building works items are met. Depending on circumstances, strengthening or alteration works may have to be carried out under the Minor Works Control System

Within 14 days after inspection of the household installations and the related alteration, rectification or strengthening works (if necessary)

PBP/ PRC is required to

  • Submit a Specified Form (MW06),
  • Submit photos and other documents to the Buildings Department

Buildings Department

After verification of the key information provided, issue an acknowledgement letter with submission number.

All works which commence after the implementation of the MWCS have to follow the law and will not be covered by the Validation Scheme.

The works will still be unauthorised building works after validation. Since at the time when they were constructed, no application to the Building Authority was made. The Building Authority (BA) cannot grant retrospective approval to such works. However, the BA will not serve an order under section 24 or a notice under section 24C of the Buildings Ordinance in respect of these validated structures on the ground that they have been completed or carried out without prior approval and consent.