Complete Guide to Aluminium Window Maintenance in Hong Kong
Walk through any neighbourhood in Hong Kong and you will see thousands of aluminium-framed windows lining the facades of residential towers. From 1970s public housing estates in Kwun Tong to luxury developments on the Peak, aluminium windows are the overwhelmingly dominant window type in the city. Their lightweight durability and resistance to the subtropical climate make them ideal — but they are far from maintenance-free. Every year, falling window components injure pedestrians and prompt emergency repairs that could have been avoided with routine care.
Why Aluminium Windows Deteriorate in Hong Kong
Hong Kong's climate is punishing on building facades. The combination of salty coastal air, typhoon-force winds, intense UV radiation, and monsoon rain accelerates wear on window frames, hinges, and seals. Most pre-2000 buildings used mild steel friction stays and rivets that corrode over time, weakening the connection between the window sash and the frame. The aluminium itself does not rust, but it does oxidise, and dirt buildup in the tracks creates friction that strains hardware during opening and closing.
Another factor unique to Hong Kong is the sheer number of casement windows that project outward over public pavements. When a hinge fails on the 20th floor, the consequences can be fatal. The Buildings Department recorded over 30 incidents of falling window parts in a single year, prompting the introduction of the Mandatory Window Inspection Scheme (MWIS).
The Mandatory Window Inspection Scheme (MWIS)
Under section 30C of the Buildings Ordinance, the Buildings Department can issue statutory notices requiring owners of buildings aged 10 years or more to have their windows inspected by a Qualified Person (QP) — a registered architect, engineer, or surveyor. The inspection covers all external windows, including aluminium casement windows, sliding windows, louvre windows, and any projecting window hardware.
- Who must comply: All private building owners who receive a statutory notice from the Buildings Department
- Inspection scope: The QP inspects every window in the flat for frame integrity, hinge condition, locking mechanisms, sealant condition, and glass stability
- Timeframe: Owners typically have six months from the date of the notice to complete the inspection and any required repairs
- Penalties: Non-compliance can result in a fine of up to HK$50,000 and imprisonment for one year
- Cost: A typical MWIS inspection for one flat ranges from HK$800 to HK$2,000, while repairs vary from HK$2,000 to HK$20,000 depending on the number of windows and severity of damage
Regular Cleaning and Maintenance
Monthly Cleaning
Use a soft cloth or sponge with mild detergent and warm water to wipe down the aluminium frames. Avoid abrasive cleaners or steel wool, which scratch the anodised surface and accelerate oxidation. Pay special attention to the bottom track of sliding windows, where dust, grit, and debris accumulate and jam the rollers. A vacuum cleaner with a nozzle attachment works well for clearing the tracks before wiping.
Quarterly Lubrication
Apply a silicone-based lubricant spray to all moving parts — friction stays, hinges, sliding tracks, and locking mechanisms. Avoid oil-based lubricants, which attract dust and form a sticky residue. WD-40 is acceptable for freeing a stuck component but should be followed with a proper silicone spray for lasting protection. After lubricating, open and close each window several times to distribute the lubricant evenly.
Annual Inspection Checklist
Even if your building has not received a MWIS notice, performing a yearly self-check is prudent.
- Hinges and friction stays: Check for rust, looseness, or excessive play. Tighten screws if they have worked loose. Replace any hinge that shows visible corrosion or cannot hold the sash in the open position.
- Rivets: Many older aluminium windows are assembled with rivets rather than screws. Look for missing or corroded rivets, which weaken the frame joints.
- Rubber seals and gaskets: Inspect the weatherstripping around the window perimeter. Cracked, flattened, or missing rubber seals allow rainwater ingress during typhoons and reduce sound insulation.
- Glass condition: Look for chips, cracks, or delamination in laminated glass. Any damage to the glass compromises wind resistance.
- Locking mechanisms: Ensure window locks engage fully. A window that cannot be securely latched is both a security risk and a wind-load hazard.
When to Replace Your Aluminium Windows
Repair is not always the best option. Consider full window replacement if you encounter any of the following:
- The frame is visibly warped, cracked, or has holes from severe corrosion
- Multiple hinges have failed repeatedly despite replacement
- The window cannot seal properly, allowing rain penetration during typhoon signal no. 3 or above
- Your building is undergoing a major renovation and the Owners' Corporation has budgeted for facade upgrades
- The existing windows are single-glazed and you wish to upgrade to double-glazed units for thermal and noise insulation
Replacement aluminium windows in Hong Kong typically cost between HK$3,000 and HK$8,000 per window, including installation, depending on size and specification. Sliding windows are generally cheaper than casement or top-hung designs. If you live in a building managed by the Hong Kong Housing Society, subsidies may be available under their building rehabilitation programmes.
Hiring a Qualified Contractor
For any window work beyond basic cleaning, engage a contractor registered under the Buildings Department's Minor Works Control System (MWCS). Aluminium window replacement falls under Class III (minor works), and the contractor should hold the appropriate registration. Always ask for the contractor's registration number and verify it on the Buildings Department website before work begins. Obtain at least three quotations and ensure the quote specifies the brand, model, material grade, and glass type to be used.