Spalling Repairs
Spalling (Concrete Cancer), often identified by flaking concrete (concrete spalling) or rust stains from within the concrete, is a serious problem. Often people mistake the signs for weathering caused by the elements, but whilst this may have a part in exacerbating the problem, the real problem lies within the concrete itself. Spalling is caused by rusted steel reinforcing from within the concrete. As steel rusts, it can expand up to 7 times its original size causing the surrounding concrete to be displaced. As the steel pushes the concrete away, more water gets to the steel expediting the process.
The process can start in many ways, but generally it is due to one of the following:
- Poorly treated reinforcing steel being used in the first place
- The ends of reinforcing being too close to the surface, allowing water to seep through concrete and react with the steel
- Incompatible metals being used on the steel causing a reaction
- Fractures in the concrete allowing water to penetrate the concrete and react with the steel
Spalled concrete is an eye-sore, but more than that it can cause a safety hazard. If pieces of concrete are left untreated they can fall from heights risking the lives of passers-by below. Spalling and delaminated concrete should be treated immediately as deferring the treatment will inevitably lead to increased problems in the future.
Similarly, treating the visual aspects such as rendering over the steel are short term solutions, as the rusting process will continue below the surface causing the steel to again displace the concrete and in some cases rust so badly the steel eventually needs replacement. Proservices has knowledgeable staff that can help ascertain where underlying issues and problems stem from. Once found, we will remove all spalled concrete, grind back the reinforcing steel to remove all rust, treat the steel with anti-corrosives and then make good the render to restore the original facade.
