The authorities are looking at ways to improve the safety of building facades, following a recent spate of incidents that saw building parts fall from Housing Board blocks.
Over the past two months, a sunshade, two ceilings and a chunk of cladding board were dislodged in four episodes. The last, which took place three weeks ago at a 51-year- old HDB block in Circuit Road, saw a piece of wall facade plummet more than 10 storeys, crashing into the driveway below.
While no one was injured, the incidents have raised concern among residents, MPs and engineers, who are calling for tighter checks, especially on older buildings.
The Building and Construction Authority (BCA) said it is looking at ways to ramp up the safety of building facades. It is "currently studying overseas regimes and looking into measures to enhance facade safety". These include systems of cities such as Hong Kong and New York.
The review comes as the oldest of Singapore's HDB blocks turn 55. Those built in the 1960s and early 1970s - making them older than 40 years - comprise less than 10 per cent of the 9,000-plus public housing blocks today.
Safeguards are in place to ensure their structural integrity: all buildings must be inspected regularly by a professional engineer.
The Periodic Structural Inspection is done every 10 years for residential buildings, and every five years for other buildings, to ensure that structural defects can be detected and rectified early, said the BCA.
Older public housing blocks are checked every five years, the HDB said. It did not specify how it defines "older" blocks.
Recent incidents in HDB estates
Oct 19, 2016: Cladding board in MacPherson
A cladding board made of calcium silicate dislodged from Block 51, Circuit Road, in MacPherson and crashed to the ground. No one was hurt in the early morning incident amid strong winds and rain. The block was built in 1965.
The Marine Parade Town Council has appointed a professional engineer and is working with HDB to inspect the block facade, as well as 24 neighbouring blocks with similar designs.
The precinct last underwent repair and redecoration works in 2014, and the cladding boards were found to be in good condition, the town council said.
Oct 17, 2016: False ceiling in Tampines
A false ceiling at the void deck of Block 807, Tampines Avenue 4, collapsed after termites attacked the wooden frame that held it up. No one was hurt in the incident.
Tampines GRC MP Baey Yam Keng said that similar wooden frames in the void decks of eight nearby blocks will be replaced with metal ones to prevent the incident from happening again.
Oct 9, 2016: Ceiling boards in Bukit Merah
Several ceiling boards fell during lunchtime at Nan Heong Ho Kee coffee shop at Block 148, Silat Avenue, nearly hitting a woman. The eatery's person-in-charge said the shop was bought over eight years ago and the ceiling was new following a major renovation.
Sept 25, 2016: Sunshade in Tampines
A concrete sunshade on the fourth storey of Block 201E, Tampines Street 23, dislodged and fell onto a sunshade on the third storey.
No one was injured, but HDB started ultrasound inspections of the sunshades in the affected block and three others with similar sunshades, all built in 1985.
July 19, 2015: Plaster slab in Choa Chu Kang
A piece of plaster about the size of a large bath towel plunged from a height of 18 storeys off the facade of Block 464, Choa Chu Kang Avenue 4, breaking on impact. The block was around 17 years old. Nobody was hurt.
HDB and Chua Chu Kang Town Council said in a statement that the plaster's dislodgement was likely caused by the "natural deterioration" of the material over time.
But such inspections cover only structural parts of a building, such as beams and columns. They exclude facade elements such as sunshades and cladding boards, which were involved in the recent incidents. Schemes like the Neighbourhood Renewal Programme also do not include checks on facade elements.
Still, the BCA stressed that facade parts "remain safe" with regular and proper maintenance. These come under the remit of town councils, charged with regular visual inspections and cyclical repair and redecoration works. The HDB also said it "selectively" conducts annual audit inspections of building facades, particularly of older blocks.
MPs and engineers welcomed the BCA review, but said more pre-emptive steps should be taken.
Ms Tin Pei Ling, one of four MPs who will raise this issue in Parliament today, said: "Perhaps the frequency of checks could be stepped up for older blocks, especially those built in the 1960s."
The Circuit Road block, built in 1965, is in her MacPherson constituency. It is not the first time facade elements have fallen in the constituency. Small tile pieces have fallen from other blocks. She said: "These are not very common, but we still have to view it seriously. It would be unfortunate if they fall and injure unsuspecting elderly people or children. We don't want people to worry about walking beside blocks."
Jurong GRC MP Tan Wu Meng wants closer attention to be paid to potentially higher-risk facade structures, such as those that bear more weight or more elaborate masonry. "The oldest blocks in my ward are about 40 years old. They were built in line with construction norms of that era. With better technology today, we should explore new ways to monitor old buildings more closely."
Engineers said the authorities' checks on blocks should include non-structural, architectural elements that could give way to wear and tear over time. These would include walkway roofs and even block number signs.
Former Institution of Engineers Singapore president Chong Kee Sen said: "We should have a targeted checklist of features that could potentially fall or give way due to ageing. This list shouldn't be exhaustive, but instead evolve and become more comprehensive over time."
SIM University's building and project management programme head Tan Teng Hooi said: "In the same way older people are affected by effects of ageing, older blocks tend to deteriorate more and should undergo more thorough checks."