Spalling Concrete

Spalling concrete is a common issue for older buildings, especially in home areas with damp conditions such as kitchens and toilets. It is largely caused by carbonation, which is a natural deterioration process. This causes the steel bars embedded in the ceiling slab to corrode, in turn causing the concrete cover to crack and bulge.

As the home owner, you are responsible for the prevention of any spalling concrete in your flat through regular maintenance, as well as any repair work required.

Here is an example of spalling concrete in a flat, and a piece of dislodged spalling concrete:

Preventing Spalling Concrete

Spalling concrete is a surface maintenance problem that occurs in reinforced concrete structures. Do not delay the repair of spalling concrete as the affected area will become larger over time.

Here are 3 ways to prevent spalling concrete in your flat:

• Paint ceilings regularly

Paint protects your ceiling and helps to prevent carbonation. Arrange to repaint your flat if you notice that the interior paint has deteriorated over time.

• Seal cracks/ holes properly

Check your ceiling regularly for any holes or cracks, which 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, such as holes left after a ceiling fixture is removed.

• Ensure sufficient ventilation

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

Repairing spalling concrete

You can repair spalling concrete in your flat on your own, if the affected area is small.  

The following steps outline how to repair spalling concrete. You may also watch this video for more details.

	Remove the spalled concrete 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 Apply a bonding agent to the affected surface to ensure proper adhesion Patch the hacked area using polymer modified cement mortar
	Paint over the patch area to match the rest of your ceiling

If the patch area is large, you should engage a contractor to repair the ceiling promptly before more concrete dislodges and potentially cause injury. When left unattended, the spalling concrete will spread to a bigger area and weaken the building structure. 

Step 1: Engage a contractor to repair spalling concrete in your flat

Here are some contractors that you may wish to consider:

Note:

• The list above is for reference only, and should not be considered exhaustive or an endorsement of any contractor’s performance.
• We recommend that you conduct additional research to find the right contractor.
• You may contact the contractors during office hours: Monday to Friday, 9:00am to 5:00pm, and Saturday 9:00am to 1:00pm. You will have to negotiate the price and scope of work with the contractor.
• You should ensure that the contractors you engage exercise due care and diligence while carrying out the necessary repair work.

Step 2: Remove loose concrete while waiting for the repair work by the contractor

While waiting for the repair work to be carried out, you should remove any loose concrete to prevent injury to your family members. Follow the following tips to ensure safety:

Wear protective gears such as a helmet, and a pair of gloves and eyewear Prepare a hammer and chisel/ long flat point screwdriver to remove the loose concrete Cover the floor and protect the surroundings with thick cardboard Secure the ladder and climb up to remove the loosen concrete Hold the affected portion of concrete and bring it down carefully
Collect the concrete debris and dispose it safely at the centralised bin collection chute at the ground level of your block