Concrete spalling or as its often refer to as concrete cancer is caused when steel reinforcement within a concrete slab begins rusting. When steel rusts it expands approximately 5 times its original size causing concrete cracking and flaking.
Once this damage occurs generally more water can enter the affected area, speeding up the process.
Generally the exact cause concrete cancer often depends on the individual circumstances of each case.
These include the steel being too close to the surface allowing water to react with it, poor quality steel, incompatible metals used close to each other causing a reaction, and damage to concrete allowing water to enter the slab and come into contact with the steel.

One of the biggest cause of concrete spalling is where Magnasite has been used as a floor topping. Magnasite was used extensively in the 70,s as a floor topping but has no become one of the biggest causes of Concrete Cancer

Spalling concrete puts owners of property at risk of negligence suits. Damage can occur through concrete pieces falling and injuring people or property. If concrete spalling that is not repaired it will leed to a greater chance if significant damage along with the increased cost of repair.
Concrete spalling cannot be repaired simply by rendering over the affected area.
Concrete Spalling requires a Specialised Remedial company that prides itself carrying out works to the highest standards and only using only the highest grade products.

 Concrete Spalling Video