When you walk into a Hong Kong apartment for a viewing, the fresh paint and polished floors can hide problems that cost thousands of dollars to fix. Structural and maintenance issues are common in Hong Kong's aging building stock, where many private residential blocks are 30, 40, or even 50 years old. A careful inspection during your visit can save you from unexpected repair bills and safety risks after you buy.

This article covers the most common defects found in Hong Kong properties, how to spot them, and what they typically cost to repair. We focus on concrete evidence you can see or test yourself, and we flag when you should call a professional surveyor. For a full overview of the buying process, see The Complete Guide to Buying Property in Hong Kong.

Water Seepage and Dampness

Water seepage is the most frequently reported defect in Hong Kong residential properties. The Buildings Department received over 15,000 seepage complaints in 2023. In a high rise city with monsoon rains and high humidity, water intrusion is a persistent problem.

Signs of Active Seepage

  • Peeling paint or wallpaper: Bubbling, flaking, or discolored patches on walls or ceilings, especially near windows, bathrooms, or external walls.
  • Efflorescence: White, powdery deposits on concrete or brick walls. This indicates water moving through the structure and depositing salts.
  • Mold and mildew: Black, green, or grey spots in corners, behind furniture, or in cabinets. Musty odors also suggest hidden dampness.
  • Warped or swollen floorboards: In older flats with wooden parquet floors, water damage causes boards to lift or buckle.

Common Sources

In Hong Kong, the most common seepage sources are leaking water pipes inside walls, failed waterproofing in bathrooms and kitchens, and rain penetration through window frames or external wall cracks. In buildings over 30 years old, the original waterproof membranes in wet areas often degrade. A typical bathroom re waterproofing job in Hong Kong costs between HKD 8,000 and HKD 20,000 depending on size and material. If the leak originates from a neighboring unit, the repair process can take months and involve mediation by the Building Management Office or even legal action. Understanding Rights and Obligations of Buyers can help you navigate such disputes.

How to Test

During a viewing, bring a small flashlight and a moisture meter if possible. Shine the light at an angle along walls to reveal subtle undulations or patches. Press your palm against walls for 10 seconds; if the surface feels cool or damp, moisture is present. Check behind bathroom cabinets and under sinks for signs of leaks. For a thorough assessment, you can hire a registered surveyor who uses thermal imaging cameras to detect hidden moisture. See Reading a Sales Brochure for tips on comparing advertised features with actual conditions.

Concrete Spalling and Reinforcement Corrosion

Concrete spalling, locally called