Another two incidents in a series of falling concrete slabs from aged buildings occurred in North Point and San Po Kong yesterday with no injuries.

A citizen reported to the police at about 7am saying concrete spalled off a tenement building at Tseuk Luk Street in San Po Kong. The 1-meter-by-0.5m concrete slab fell from a canopy of the 62-year-old building.

Police officers and firemen cordoned off the area to clear the concrete debris on the ground and inspected the building with Buildings Department officers.

Potentially loose concrete was also removed.

About two hours later, a private car owner reported another concrete-falling incident in North Point, where a piece of concrete fell off a carpark ceiling from the 44-year-old Healthy Gardens.

The concrete chunk, measuring about 1.5m by 1m, struck a parked seven-seater sedan at 9.22am.

The fallen concrete dented the roof and rear of the vehicle. Repair workers were called to the scene and tore down pieces of damaged concrete.

The reinforcing steel was clearly visible with concrete debris strewn over the floor, as workers inspected the damage.

The department has been looking into the causes of the two incidents.

Meanwhile, a 'preventive maintenance' strategy has been adopted in the construction and management of the third block of the eResidence project in Hung Hom, which can extend the building life from 50 years to 75 years, said Urban Renewal Authority managing director Wai Chi-sing, as the newest block will be opened for application next month.

Wai said the authority consultants had studied with Ray Su Kai-leung, civil engineering associate professor at the University of Hong Kong, to formulate concrete proposals on the structural design and the construction materials that can be used to extend the building's lifespan.

Upon receiving a report, the authority decided to use reinforcing bars which are more resistant to corrosion, as well as to adjust the ratio of the concrete materials and use high-strength concrete to enhance the load-bearing capacity of the building structure, in order to provide a safer living environment for residents.

Wai said applying these measures will involve an additional construction cost of about HK$2 million, which will only account for about less than 1 percent of the total construction cost of the project.

"But it is sufficient to achieve the effect of prolonging the buildings' lifespan and it is worthwhile for the architectural and engineering sectors to draw reference from," he said.

The authority will also consider adopting preventive maintenance measures in their next project in Tai Hang Sai Estate.

Two more concrete chunks fall from heights