What is concrete spalling?
Concrete when used in construction, needs to be reinforced with steel, in the form of bars or mesh. However, when exposed to air or water, steel corrodes, which causes it to expand. The expansion of the steel causes the surrounding concrete to crack, and therefore undermine the strength of the building. The cracking or break down of the concrete is known as spalling. The cancer aspect is due to the progression of the corrosion of the steel spreading through the inside of the concrete. Once the concrete cracks, it further exposes the steel to the atmosphere, and the process continues.

What are the usual causes of concrete cancer?
The porous property of concrete is something which can be affected by the quality of the constituent ingredients in the concrete materials, such as aggregate. Another cause is the presence of chlorides in salt water can enter the concrete after it is built, and cause corrosion. This is an issue with buildings near the ocean, such as beach apartment blocks. Other factors causing the exposure of steel to the elements include building defects, for example the concrete not being set properly, or not effectively covering the steel. Environmental factors such as the movement of earth under the building can cause the concrete to crack, thereby exposing it to the elements, or water soaking up from underground. Weathering and erosion of concrete, as well as exposure to chemicals such as acid or even bacteria can undermine concrete. Temperature and climate are also factors which can cause concrete to break down, as water can freeze and thaw on its surface.

How common is this problem in existing buildings and houses?
Concrete cancer is very common in existing buildings and houses especially the ones that are along the coast.

What are cost implications of concrete cancer for building owners?
The cost implications for building owners are dependent on the severity of the problem, the sooner the problem is addressed the less it will cost for the building owner. In some cases where the severity of the spalling is so extreme where it is not feasible to repair the structure will be rebuild.

How is concrete cancer usually repaired?
BCMGs repair mechanisms include an analysis of the site by visual observation and concrete hammer testing. Following this, BCMG repair the deteriorated concrete using breakers to expose the corroded area of reinforcement. We cut around the affected areas using quality saws, taking care to leave respectable looking edges. In some instances we are required to hydro demolish areas using highly pressured water. Reinstatement of the concrete is then undertaken in accordance with required standards and manufacturers instructions. As a final measure, surfaces are tailor-coated after careful surface preparation and liaison with clients regarding need. Effective application of protective coating systems will ensure that the concrete is protected to slow down further future effects of corrosion, carbonation or physical damage.

How can concrete cancer be prevented?
Using less corrosive internal reinforcements is one option like hot dip galvanized reinforcement. Coating the concrete in a waterproofing membrane is another option, especially if the membrane contains chemicals which are resistant to chloride.

How can BCMG help building owners who are affected be concrete cancer?
At BCMG we really strive for excellence in the area of concrete repair. The key to maintaining the properties and strength of concrete is regular and systemised maintenance. We are able to service all your structural, spalling and construction repair needs in a professional manner. Our team of highly qualified staff are at your back and call to complete your project in a safe and competent manner. At BCMG we take time to thoroughly assess the cause of deterioration before analysing and deciding upon what course of action to take. Our clients are offered a thorough customised report outlining the research findings.