Concrete Spalling (Concrete Cancer) – Causes, Prevention & Repair | Waterproofing SG

What is Concrete Spalling (Concrete Cancer)?

Concrete spalling, also known as concrete cancer, is a serious structural issue that
a􀆯ects buildings in Singapore’s humid and tropical climate. It starts with surface
staining, followed by cracking, flaking, and separation of concrete from the a􀆯ected
areas. While many believe it is caused by weathering, the real culprit is corrosion of
the steel reinforcement within the concrete.

What Causes Concrete Spalling?

Concrete spalling occurs when moisture and oxygen reach the steel reinforcement
bars (rebar) within the concrete. As the steel rusts, it expands up to five times its
original size, causing the concrete to crack, weaken, and eventually break away.
Several key factors contribute to this issue:

1) Steel Reinforcement Placed Too Close to the Surface

• If rebar is positioned too close to the concrete surface, moisture infiltration
  happens faster, leading to premature rusting and expansion.

2) Poor-Quality or Incompatible Materials

• Low-quality steel that rusts quickly.
• Using incompatible metals close to each other, triggering an
  electrochemical reaction that accelerates corrosion.

3) Structural Damage Allowing Water Ingress

• Cracks in concrete caused by aging, heavy loads, or movement.
• Poor waterproofing that allows moisture penetration.

4) Carbonation

• Over time, CO₂ from the air reacts with calcium hydroxide in concrete,
  lowering its pH and making it less protective against steel corrosion.

5) Chloride Exposure (Common in Coastal Areas)

• Buildings near the sea or exposed to chloride-laden water (such as
  swimming pools) suffer from faster rebar corrosion due to salt infiltration.

Why Concrete Spalling is a Major Concern

Safety Risks

Concrete spalling poses a serious hazard. Falling concrete can cause injury
or property damage, leading to potential legal liabilities for property
owners.

Increased Repair Costs

Ignoring early signs of concrete spalling will escalate repair costs as the
damage spreads deeper into the structure.

Structural Weakness

If left untreated, concrete cancer can compromise the integrity of a
building, affecting its load-bearing capacity and lifespan.

How to Identify Concrete Spalling?

Common visible signs of concrete cancer include:

• Surface cracks & discoloration.
• Rust stains appearing on concrete surfaces.
• Flaking or chipping concrete.
• Exposed rebar with visible rust.
• Hollow sounds when tapping concrete surfaces.

If you notice any of these signs, it is crucial to act immediately to prevent further
deterioration.

How to Prevent Concrete Spalling?

1) Proper Waterproofing

• Applying high-quality waterproofing membranes and coatings prevents
  moisture penetration, reducing the risk of rebar corrosion.

2) Quality Construction Practices

• Ensuring correct concrete mix ratios for strength and durability.
• Using proper reinforcement placement techniques to prevent early
  exposure.

3) Corrosion-Resistant Reinforcement

• Galvanized or epoxy-coated rebar provides better protection against rust.
• Stainless steel reinforcement for structures exposed to marine
  environments.

4) Regular Maintenance & Inspection

• Routine building inspections to detect early signs of spalling.
• Addressing cracks and leaks before they allow water infiltration.

Concrete Spalling Repair Solutions by Waterproofing SG

Concrete spalling cannot be fixed by simple patching or rendering—a proper
restoration approach is required. At Waterproofing SG, we specialize in grouting and
injection services, offering long-lasting repair solutions.

Step-by-Step Repair Process

1. Inspection & Assessment: Identify the extent of the damage with a thorough structural evaluation.
2. Removal of Affected Concrete: Loose and deteriorated concrete is chiseled away to expose the damaged reinforcement.
3. Reinforcement Treatment: Rusted rebar is cleaned, treated, or replaced to prevent further corrosion.
4. Application of Repair Mortar: A high-strength repair compound is applied to restore structural integrity.
5. Waterproofing & Coating: To prevent future moisture ingress, a protective sealant or waterproofing membrane is applied.

Why Choose Waterproofing SG for Concrete Spalling Repair?

• Expertise in Structural Repairs & Waterproofing – We specialize in long term concrete restoration.
• Advanced Grouting & Injection Solutions – Cutting-edge techniques to seal cracks and prevent water penetration.
• High-Quality Materials – We use durable, corrosion-resistant materials that enhance concrete longevity.
• Affordable & Reliable Services – Competitive pricing with no hidden costs.

Frequently Asked Questions (FAQs)

1) How long does concrete spalling repair last?

When done professionally, spalling repairs can last decades, especially with proper waterproofing and maintenance.

2) Can I fix concrete spalling myself?

DIY repairs only offer temporary fixes. Without addressing the underlying steel corrosion, the issue will reoccur.

3) How much does it cost to repair concrete spalling?

Costs depend on the severity of damage and the repair method. Contact Waterproofing SG for a free inspection and quote.

4) Is concrete spalling common in Singapore?

Yes, due to high humidity, heavy rainfall, and coastal exposure, Singapore buildings are more prone to concrete cancer.

5) How do I prevent concrete cancer in my property?

Regular building inspections.

• Applying waterproofing coatings.
• using high-quality construction materials

6) How soon should I repair concrete spalling?

Immediately! The longer you wait, the more extensive and costly the repairs will become.

Don’t let concrete spalling compromise the safety and longevity of your property. Contact Waterproofing SG today for expert diagnosis and long-term repair solutions.