The importance of spalling is often overlooked and is often left untreated. Sometimes the delay of repairing spalling can result in major structural damage, excessive repair costs, damage to property and it can even put lives at risk from the falling of loose concrete.

Areas with high moisture levels, especially along South Africa’s Indian Ocean, with its relentless rainfall, sea spray and high winds, pose a threat to the structural integrity of buildings.

Water ingress can cause more than just leaking and peeling – it can lead to dangers associated with spalling.

This is according to Spalling Worx managing director, Kevin McGeer, who says spalling is especially common in the Durban, due to the high moisture in the atmosphere during the wet summer months. He says a further leading contributor to spalling is the higher salt content in the atmosphere. He says cracks in building structures can often also be attributed to corrosion of the internal steel reinforcing bars.

Kevin says unreinforced concrete tensile strength is relatively low compared to its compressed strength, so steel reinforcing is placed, for its high tensile strength, inside concrete columns that are susceptible to high tensile forces, especially high-rise buildings. He says untreated damage to this steel can lead to the onset of early deterioration of a building’s structure.

Spalling is a result of water ingress that reaches into the structures of buildings causing surface peeling or flaking due to moisture in the concrete. This moisture, coupled with a high salt content that introduces chlorides into the concrete, pushes out from inside the structure while attacking the integrity of the steel reinforcing causing corrosion that breaks down the protective layer around the steel bars, weakening them, leading to the destruction of the building’s exterior structure.

“As cracks expose more of the steel reinforcement, corrosion is exacerbated and the steel will deteriorate at an increasingly rapid pace. The more the steel corrodes, the weaker the building’s structure becomes and less reliance can be placed on the strength the steel originally provided. Left untreated, the steel reinforcement will lose its bond with the concrete and the structure may collapse under its own weight.”

Spalling is a common maintenance problem and is more prevalent in older buildings. Bodies corporate, building owners and property managers need to be aware of the dangers of spalling in Durban’s high rainfall, wind and sea spray regions. If identified and treated, the integrity of the building will remain unaffected.

Kevin shares a few tips on how to prevent spalling…

  1. Seal cracks and holesas soon as possible to prevent prolonged exposure of any reinforcing steel.
  2. Ensure that exposed steel is assessed for corrosionand is then treated.
  3. Ensure adequate waterproofingon surfaces exposed to high rainfall, wind or sea spray.
  4. Implement a maintenance programme that includes a painting plan tailored for specific weather conditions.
  5. Ensure adequate sealing of holes when adding substructures such as tanks, satellite dishes etc. to walls or roofs.

Spalling repairs are a time consuming, often difficult task. Identifying the source and extent of the damage requires extensive testing. This involves chipping away the concrete to expose the corroded steel reinforcing to ascertain the depth of the problem. The corroded steel needs to be scraped to remove all the rust and anti-rust paint needs to be applied followed by a bonding agent to ensure proper adhesion to the concrete. Mortar is then re-applied over the steel before painting the surface.

Kevin says underestimating the damage resulting from spalling is dangerous. He says if ignored, it may lead to larger more costly repairs and even building condemnation. He adds that regular maintenance checks will allow you to identify problem areas early enough to treat the problem and maintain the structural integrity of the building.

For in depth specification, please contact the writer on 083 600 3037

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