Conspar recently carried out concrete repair work for a busy restaurant in Northbridge.
Conspar director Byron Spartalis said an area of the building had showed signs of concrete cancer and needed treatment.
"There was concrete cancer underneath the concrete stairway, on the soffit," Byron said.
"It had been caused by a water ingress problem.
"The steel reinforcement in the concrete was becoming affected causing the concrete to break out - what we call 'spalling'."
Byron said the steel had to first be uncovered before it was treated, which included knocking out any loose concrete to expose it.
Once the rust on the steel was removed and the structure treated to prevent further rusting, the concrete was reinstated and the area rendered for a smoother finish ready for painting.
The staircase was also waterproofed to help prevent concrete cancer from occurring in the future.