The Housing Board yesterday embarked on an ultrasound inspection of the sunshades in four Tampines blocks.
This comes after a concrete sunshade on the fourth floor of Block 201E, Tampines Street 23, fell off on Sunday and landed on another sunshade on the third floor.
No one was hurt and the cause is being investigated. But the four-storey building has been found to be structurally safe by HDB engineers.
HDB said it will use ultrasound scanning equipment to check the sunshades at the affected block and three other blocks with similar sunshades - Blocks 201A, 201B and 201D in Tampines Street 21. The four blocks, which were built in 1985, are home to 181 households and have 73 sunshades.
HDB said the ultrasound scan "seeks to assess the condition of each sunshade, including the presence of reinforcement bars embedded within the sunshades".
The presence of metal reinforcement bars, and whether they were properly put in place, is one area of HDB's probe into the incident. The ultrasound scanner transmits magnetic waves into the concrete and detects the presence of the bars.
When The Straits Times visited the site yesterday, scaffolding and safety barriers had been erected for the checks, and a laboratory tester engaged by the HDB was scanning a sunshade at Block 201E.
Checks at the block will be completed in a week and later carried out at the other blocks. When asked if other types of sunshades will be checked, the HDB said its "immediate priority" is these four blocks.
HDB and Tampines Town Council will repair the sunshade on the third storey hit by the dislodged sunshade, which has been taken for checks. Urging the public not to speculate, HDB said: "To get a complete and accurate picture of the cause behind the incident, we need both the laboratory investigation and site checks to run their full course."
MP for Tampines GRC Cheng Li Hui, who observed the checks yesterday, said: "Some of the residents are concerned because they are worried about the safety of the third level (sunshade)."
She said engineers have certified this sunshade, the one that was hit, is safe and it has been secured by tension cords as a precaution.
Sales executive Benjamin Tan, 32, who lives in Block 201E, said he is worried that other sunshades might fall and hit someone. "It's a good thing they are checking them. There are shops and a coffee shop below and a lot of people walk past all the time."