What Is Concrete Cancer? A Hidden Risk in Older Properties

Concrete cancer might sound dramatic, but it’s a real threat to buildings—especially older ones. It occurs when steel reinforcement inside concrete begins to rust, causing the concrete to crack and deteriorate.

Here’s how it happens:

• Water and air seep into the concrete, reaching the steel reinforcements.

• The steel rusts and expands, cracking the concrete—a process called spalling.

• Cracks allow in more water, accelerating the damage.

Common causes include:

• Salt air or water exposure (coastal areas are at higher risk).

• Poor construction or waterproofing.

• Chloride contamination (e.g., from de-icing salts).

Signs to watch for:

• Cracks, especially near reinforcement.

• Rust stains on concrete surfaces.

• Bulging concrete or water leaks.

Why it matters:

• It weakens structural integrity—seriously.

• It creates safety risks.

• It’s expensive to repair if left too long.

Preventative tips:

• Schedule regular inspections.

• Ensure good waterproofing.

• Use corrosion inhibitors where needed.

Takeaway:

If you’re buying at auction, especially coastal or older properties, a structural survey is a smart move. Catching concrete cancer early can save thousands.