After picking up the keys in June to a flat in King Hei House intended for his 79-year-old mother, Mr. Tsang found that the kitchen and bathroom surfaces suffered from extreme dampness. Floor sensors registered moisture levels at 99 percent in the washroom, while wall readings hovered between 60 and 70 percent. Over the subsequent five months, the Housing Department dispatched repair crews at least three times to tackle the issue, culminating in the removal of low-level wall tiles, floor tiles, and waterproofing layers by late August.
Contractors conducted an eight-hour ponding test in late August, declared the area leak-free, and reapplied the waterproof membranes before laying new tiles on October 21. Yet when HK01 inspected the property alongside engineering supervisor Vincent Ho Wai-kin on October 25, the problem persisted. Instruments measured the washroom floor humidity at 92.6 percent, with kitchen floors at 73.2 percent, prompting the expert to declare that the unit failed basic delivery standards and harbored hidden water accumulation.
Construction Methods and Trapped Moisture Under Scrutiny
The persistent dampness points directly to complications arising from Modular Integrated Construction, commonly known as MiC. Under this method, independent volumetric units are manufactured off-site in factories before being hoisted and assembled at the construction location. Ho explained that buildings erected via MiC during rainy weather risk trapping rainwater between stacked modules if the surfaces of individual boxes are not thoroughly dried before being sealed with concrete.
Traditional buildings feature solid concrete floor slabs, whereas MiC developments incorporate hollow floor designs between boxes. Even with designated drainage holes, complete water expulsion during wet weather remains difficult to guarantee. The application of exterior wall paint reportedly prevented trapped moisture from escaping outward, leaving visible water marks on interior walls as proof of internal pressure.
Beyond the underlying humidity, the repair work itself introduced secondary defects. An inspection of the newly laid kitchen flooring revealed that roughly half of the tiles were hollow underneath. Ho noted that excessive surface moisture prevents the adhesive mortar from bonding correctly to the subfloor, creating hollow pockets that compromise structural integrity and risk future tile displacement.
Official Denials and the Stalled Move-In Timeline for Residents
The Housing Department strongly rejected any link between the defects and MiC construction techniques. In its official response, the agency completely ruled out the possibility of rainwater accumulating between precast components during the building phase. On-site checks reportedly confirmed that concrete surfaces beneath the waterproof layers were dry, and partition walls showed no signs of seepage.
The department attributed the initial water marks to minor shrinkage gaps around gas pipe apertures in the kitchen and a damaged drainage connection pipe in the bathroom, noting that these points had been repaired and that contractors had replaced the hollow tiles upon follow-up. Despite these assurances, Mr. Tsang left his flat undecorated, fearing that drilling into walls or installing fixtures would prompt the housing authority to blame him for the alterations.
With a market purchase price approaching HK$2 million, monthly mortgage payments around HK$8,000, management fees of HK$625, and an ongoing public housing rent of roughly HK$1,800 for his mother’s current flat, the financial strain continues to mount. Although the Housing Department temporarily deferred an earlier demand for his mother to vacate her public housing unit in August, the lack of a permanent resolution leaves the family in limbo.
Ho advised cutting 30-millimeter drainage holes at strategic high and low points along exterior walls and seepage cracks—provided structural safety is maintained—to allow trapped water to drain naturally. Until such measures are undertaken, the flat remains unoccupied, raising broader questions about quality assurance in modern modular housing projects across the city.
