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Concrete Repairs

While concrete itself is made up of a mixture of sand, cement, blue metal and water, bars of steel reinforcement are also usually incorporated within the concrete, in order to significantly increase the overall tensile strength (particularly in bending) of the slab or structure.

However, over time, the concrete surface may develop cracks, which may then allow water to penetrate within the concrete and then contact the steel reinforcement. Once this process begins, typical untreated steel reinforcement will begin to corrode within the concrete, which would eventually lead to a build-up of rust over the steel. This effective expansion of the reinforcement then displaces the surrounding concrete, causing extensive cracking and therefore significant weakening of the structure.

This problem is known as “concrete cancer” and should be diagnosed and treated as quickly as possible, as if left untreated, will continue to deteriorate and ultimately become structurally unsound. This issue is of particular concern for concrete that is close to the ocean or harbour, due to the salts in the atmosphere leading to much more rapid and greater severity of corrosion.


  • Cracking or crazing of the concrete
  • Spalling or scaling of the concrete, including flaking of the surface
  • Penetration of water within the concrete
  • Concrete cancer, due to corrosion of the steel reinforcement within the concrete
  • Discolouration, including rust staining
  • Formation and build-up of salts, efflorescence, grime, mould and mildew
  • Structural deformation (due to overload, for example, by displacement by tree roots)


  • Rectifying/filling cracked or crazed concrete
  • Remove deteriorated/damaged concrete, remove corroded steel reinforcement, treat rusted steel reinforcement and/or replace with galvanised type steel reinforcement and lay new concrete
  • Apply a waterproofing membrane to the concrete surface (such as to areas where the concrete is to be tiled), to prevent water penetration within the concrete
  • Apply a concrete penetrating sealer, for exposed concrete
  • High pressure cleaning of the concrete surfaces