When selecting a supplier to carry out any concrete repair work you really need to ensure you are choosing a supplier that has the correct training and licensing. This is to help protect your building and also your liability if the job is not done correctly.
‘Do you have an open builder’s licence that allows you to carry out structural work?’
Sunshine Coast Concrete Repairs is a fully licensed building company and can carry out structural work.
‘Have you had concrete repair training from the Australasian Concrete Repair Association (ACRASSOC)?’
ACRASSOC is the industry body in Australia and Sunshine Coast Concrete Repairs regularly attends training workshops to ensure best practices are followed.
‘Have you been fully trained by the product supplier in the use of their product?’
There are many aspects to applying concrete repair products and it is important to do so in accordance with up-to-date knowledge from the supplier. Sunshine Coast Concrete Repairs regularly attends training workshops conducted by their various suppliers.
Concrete cancer is when the steel reinforcement in concrete oxidises (rusts) and expands to the point the binding in the concrete gives way leading to the tell-tale cracks and spalling. This rusting of the steel dissolves the important reinforcement and severely compromises the strength and stability of the concrete.
Spalling is one of the tell-tale signs of concrete cancer where pressure from within the concrete has forced chips and fragments to separate from the surface and burst outward. Often the indication of much greater issues deeper under the surface, left untreated this can severely compromise the integrity of the concrete and the structure of buildings.
Chipping and cracking can be an indication of spalling (see above) but may also come from the pouring and curing stage of concreting. They often open avenues for water to reach the steel reinforcement so are important to correct as soon as possible.
Delamination is where the concrete splits into layers and given time may start to flake. If delamination is extensive it can indicate that the strength and stability of the concrete is compromised. Usually delamination occurs during curing after concrete is poured.
When the reinforcement within concrete comes into contact with water it often introduces the steel to corrosive elements such as carbon dioxide or chlorides. These corrosive elements affect the steel causing disintegration of the iron replacing it with rust. Rust has a weak structure but requires more volume than the original steel.
Chlorides such as salt are highly water soluble and can rapidly oxidise iron and steel when it comes into contact. Oxidisation from chlorides is often referred to as ‘green rust’ and is more prevalent if the concrete is close to water or the ocean.
As a rule of thumb, you should expect the reinforcement within concrete that has begun to oxidise to deteriorate at a factor of five times per year. 1 cm of rust the first year would likely be 5 cm the following year, then 25cm the year after, and so on. If left untreated for any length of time a small repair job can quickly become a major building project.
Quite often it is the Body Corporate within buildings that decide when and how to act on the signs of potential concrete cancer. As you can see from the above information, a patch-up repair or resurfacing will quickly lead to much greater issues so it should be done right by properly qualified specialists. Body Corporates should consider the following questions when deciding on a course of action regarding concrete repair:
Are you using a practitioner who has an open builders licence necessary to carry out structural works should they be required?
Does your practitioner have the necessary training in the use of specialised concrete repair products and techniques?
What will be the impact of the repair work on your building and its residents, and will you need to cater for closures while the repair work is undertaken?
If you put off getting the repair work are you prepared for the damage to be much greater in the near future given the rate of decay of concrete cancer?
A very important responsibility of making decisions as a member of a Body Corporate is that you could be personally liable if you try to cover or hide structural defects, or if your decisions result in inadequate maintenance during your tenure. Please ensure you protect yourself and your building by using the right people in a timely manner for concrete repair work.