The legislator pointed to long wait times for inspections among sites participating in the Urban Renewal Authority’s “Operation Building Bright 2.0”, which could take up to five years depending on a structure’s level of risk.

Leung said he hoped to shorten the maximum waiting period to two years, to ensure repairs could start as soon as possible.

“We also want to ask if residents see any of the defects we mentioned, please tell us … if there is an immediate risk, we will tell the government, so we can defuse these ‘bombs’ in the community,” he added.

As part of the joint report, both groups identified 47 buildings on Hong Kong Island that fell under the government’s inspection requirement.

The structures were categorised as “three-nil” because they lacked owners’ corporations, residents’ groups and were not maintained by property management companies.

The researchers adopted what they called “a rapid inspection” methodology by using drones and an infrared thermal scanner to uncover 25 buildings with defects that were categorised as posing “immediate risks”.

The most common issues found were building finishes that could fall off and cracks, as well as rust and water stains.

The report listed premises on 123 Wan Chai Road as an example, with the building featuring a concrete platform with signs of curvature and structural damage.

But the DAB and institution stopped short of revealing the addresses of other potentially dangerous buildings, saying such information could stoke unnecessary concerns among the public.

The Post has contacted the Buildings Department and Development Bureau for comment.

Institution founding president Tony Yu Lik-sang advocated the use of a “rapid infrared thermographic survey”.

Lawmaker Leung explained that the process involved using thermal scanners to detect temperature differences and potentially identify “water trapped inside” buildings that could affect their structural integrity, with inspectors then visiting the sites to spot defects.

But institution honorary president Marvin Chen stressed the process was for a quick review of structural safety for high-risk buildings and no substitute for a full check by a registered inspector.

However, Vincent Ho Kui-yip, building policy panel chairman for the Hong Kong Institute of Surveyors, argued that infrared scans were not foolproof and property owners should take responsibility for safety checks.

He noted that infrared scanners could only detect differences in temperatures on a building’s surface, adding that heat generated by air conditioners could paint a misleading picture.

“The government can only identify and settle those buildings with obvious risks as other buildings will still age after typhoons and rainfalls,” he said. “Owners have to conduct inspections.”

Hong Kong has recorded at least 18 incidents of concrete and debris falling from buildings since July, with some cases leading to pedestrians being injured or damaging vehicles.

In one case on August 8, a concrete chunk from the facade of a 57-year-old building in Mong Kok fell and hit a double-decker bus, making a hole in its roof.

The debris hit a KMB bus on route 30X outside the building, according to police. “The concrete caused a 30cm-by-45cm [11 inches-by-18 inches] hole in the roof of the bus,” a force spokeswoman said.

On July 19, a 27-year-old man was injured as he passed by Lai Wan Building on Shau Kei Wan Road in Sai Wan Ho when pieces of concrete fell from a canopy on the first floor, sending fragments scattering across the ground.

Secretary for Development Bernadette Linn Hon-ho earlier said 900 buildings had failed to comply with mandatory inspection orders, 30 of which would undergo emergency repairs by the Buildings Department after drones were used to complete preliminary checks.

The minister had also said the department would conduct maintenance works for another 1,100 ageing buildings. About 400 were undergoing inspections, while the remainder were undergoing repairs, she added.