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Spalling Concrete

Spalling concrete is a common issue for older buildings. It is largely caused by carbonation, a natural deterioration process. This causes the steel bars embedded in the ceiling slab to corrode, which in turn causes the concrete cover to crack and bulge. As the owner, you are responsible for the repair of any spalling concrete in your flat.

How to prevent spalling concrete

Spalling concrete is a surface maintenance problem that occurs in reinforced concrete structures. If attended to immediately, the building’s structural integrity will not be affected.

Here’s how spalling concrete can be prevented:

Paint ceilings regularly

Paint protects your ceiling and helps to prevent carbonation. Ideally, you should paint your ceiling regularly.

Seal cracks/ holes properly

Check your ceiling regularly for any holes or cracks. These should be sealed immediately to prevent moisture and carbon dioxide from entering the concrete. Similarly, seal up any holes drilled into the ceiling that are no longer in use (e.g. holes left after a ceiling fixture is removed).

Ensure sufficient ventilation

A humid environment will speed up carbonation. To reduce the humidity in moisture-prone areas such as the kitchen, toilet, and bathroom, open the windows, vents, or doors when the areas are not in use.

Repairing spalling concrete

With regular maintenance, spalling concrete within HDB flats will usually be minor and can be easy repaired. However, if the spalling concrete is left unattended over a long period, it will spread to a bigger area and weaken the building structure.

The steps below briefly show how spalling concrete is repaired. For more details, please watch this video.

While waiting for the repairs, do remove any loose spalling concrete to prevent injury to your family members.

Step 1: Remove the spalled concrete

spalling concrete repair 1
  • Remove the concrete at the spalled areas to expose the corroded steel bars

Step 2: Clean and paint the corroded steel bars

spalling concrete repair 2

  • Scrape and clean the exposed steel bars and use a wire brush to remove any rust
  • Apply 2 coats of anti-rust paint to the steel bars

Step 3: Patch the hacked area

spalling concrete repair 3
  • Apply a bonding agent to the affected surface to ensure proper adhesion
  • Patch the hacked area using polymer modified cement mortar

Step 4: Paint the area

spalling concrete repair 4
  • Paint over the patched area to match the rest of your ceiling


Repair Contractors

You can engage any of the following contractors to repair spalling concrete in your flat.

Company Name

Contact Person name

Mobile No.

Tel No.


Areas in charge

Liong Construction Pte. Ltd.

Mr Jonas Ng



North & West of Singapore

Aik San Construction Pte Ltd

Mr Teo Wei Cheng


(ext 201) 

East Singapore

Success Forever Construction & Maintenance Pte Ltd

Mr Jack Oei



Central and South Singapore


1) Our list only serves as a guide and is not meant to be exhaustive or an endorsement of the contractor’s performance.

2) You might want to also consult sources such as the Yellow Pages (Commercial/ Industrial Guide) before engaging a contractor.

3) You may contact/sms/email the contractor during working days, Monday to Friday from 9.00am to 5.00pm.

4) If you would like to engage any of the above contractors, you will have to negotiate the price and extent of work with the contractors on a private basis.

5) You need to ensure that the contractors you engage exercise due care and diligence while carrying out the necessary repair work.