A six-year-old boy was injured after being hit by concrete that fell from his Housing Board (HDB) flat's toilet ceiling due to wear and tear on Tuesday.

Facebook user Syasha DanialAlissa described the incident in their Henderson Road home as "the worst nightmare" for her and her son, who had been shooting water at the ceiling with a shower head when the concrete fell on his back.

One of the photos that Ms Syasha shared in her Facebook post shows the child with dirt, debris and blood on his back. She also posted updates about her son receiving treatment in the hospital and videos showing workers clearing debris from her flat.

She later said in another update that the authorities, including the police, HDB and town council, arrived at her flat to check the situation.

Ms Syasha said that her son, who had an X-ray scan and his wound dressed at the hospital, was fine and did not require stitches.

She added that the ceiling was already cracked prior to the incident.

Responding to queries from Stomp, HDB said yesterday it was alerted to an incident of spalling concrete on Tuesday afternoon and visited the flat on the same day. Spalling concrete was found in the ceiling of the toilet.

The board said that spalling concrete occurs when steel bars embedded in the ceiling start to corrode due to the ingress of moisture and acidic elements. Over time, this causes the concrete ceiling cover to crack and fall off.

"This is a natural wear and tear process which occurs in older buildings, such as in this flat which is 45 years old. It tends to occur more frequently in moisture-prone areas such as the kitchen and bathrooms, where the humidity will speed up the carbonation process.

"However, spalling concrete is non-structural in nature and will not affect the building's structural integrity," HDB added.

The board said that it has helped the family to clear the debris and will be carrying out repair works in the flat today. As the affected home is a rental flat, HDB will bear the cost of repairs. "With regular maintenance, spalling concrete... if it occurs, is usually minor," it added.

Flat owners who detect signs of spalling concrete are advised to carry out repairs early to prevent the problem from deteriorating further and affecting a larger area.

"In the event rental tenants discover any defects such as spalling concrete or a ceiling leak, they should report to HDB so that it can carry out the necessary repairs."

More details on the repair works are available on HDB's website.