Corrosion in reinforcement steel

Problem - Corrosion of reinforcement steel
This is the most common type of damage to occur in concrete. As corroding steel expands, it causes the concrete surface to crack and the paint to flake off.

Possible causes

  • The reinforced steel is too close to the surface.
  • Aged concrete, i.e. the alkalinity of the concrete encasing the reinforcement steel is below critical levels. When carbonation occurs in concrete, the steel corrodes if the concrete remains wet due to weather.


Clean dirt, dust, and flaked paint from the surface with a high-pressure washer or wet sandblasting machine. If the corrosion is extensive and the paint coat is completely damaged, remove the paint entirely with a wet sandblasting machine. Remove the loose, damaged concrete and cut away the damaged area. Carefully remove any rust.

Treat the cleaned steel with Tikkurila Finnseco-KOR anti-corrosion paint and repair the damaged concrete with Tikkurila Finnseco concrete repair mortars.

Paint the surface with a suitable Tikkurila façade paint or coating according to instructions.

Repair extensively corroded concrete facades with the Tikkurila Thermodek Supplementary Heat Insulation System.