Spalling concrete is a common maintenance issue faced by residents of older HDB (Housing and Development Board) flats in Singapore. While it may initially appear to be a cosmetic problem, it can indicate deeper underlying issues if left untreated. This article aims to explain what spalling concrete is, why it occurs, how it can be managed, and what residents should do when they encounter it.

What Is Spalling Concrete?

Spalling concrete refers to the flaking, cracking, or breaking away of the concrete surface, typically on ceilings or walls. It is often accompanied by rust stains, exposed steel reinforcement bars (rebars), and chunks of dislodged concrete. In HDB flats, spalling concrete is usually observed on ceilings of bedrooms, kitchens, bathrooms, and sometimes corridors.

Causes of Spalling Concrete

The primary cause of spalling concrete in HDB flats is the corrosion of embedded steel reinforcements. Several factors contribute to this:

1. Moisture Ingress: Over time, moisture penetrates through hairline cracks or porous concrete and reacts with the steel rebars, leading to rust. As the rebars corrode, they expand and exert pressure on the surrounding concrete, causing it to crack and fall off.

2. Age of the Building: Flats that are over 20 years old are more susceptible due to natural wear and tear, especially if maintenance has been neglected.

3. Poor Construction Practices or Materials: In some cases, the use of poor-quality concrete or improper cover depth over rebars may accelerate deterioration.

4. Environmental Factors: High humidity, especially in bathrooms or kitchens, can speed up the corrosion process.

Is It Dangerous?

Spalling concrete is not a structural defect and does not compromise the overall safety of the building. However, if ignored, it can worsen over time and lead to falling debris, water seepage, and further deterioration. More importantly, untreated spalling can lead to costlier repairs later on.

What Should Residents Do?

If you notice signs of spalling concrete, you should:

1. Report Early: Notify HDB or your Town Council if you live in a rental flat. For sold flats, you may need to engage a contractor or apply under the Home Improvement Programme (HIP) if your block qualifies.

2. Engage Professionals: Only trained contractors should handle spalling repairs. The repair process involves removing loose concrete, treating the corroded steel, applying anti-rust coatings, and patching the surface.

3. Preventive Measures: Residents can help prevent spalling by ensuring proper ventilation to reduce humidity, avoiding drilling near ceilings unnecessarily, and performing regular maintenance checks.

HDB’s Role and Assistance

For owner-occupied flats, HDB provides a 10-year goodwill repair period from the date of completion. Beyond that, flat owners are responsible for the upkeep. However, under the HIP or Neighbourhood Renewal Programme (NRP), repairs may be subsidised or carried out as part of estate upgrading initiatives.

Conclusion

Spalling concrete in HDB flats is a manageable and fixable issue when detected early. While it may be unsightly and inconvenient, it is not structurally dangerous. With timely maintenance and awareness, residents can maintain the comfort and safety of their homes, ensuring that their flat remains a valuable and durable asset for years to come.