27/05/2015
When it comes to combating the effects of corrosion on concrete buildings, many specifiers may feel the need to adopt a ‘make do and mend’ approach, for budgetary reasons or other constraints.
However such approaches might end up being counter-productive, especially when you consider the amount of effort required to patch a high-rise concrete building.
Concrete Repair in High-Rise Buildings
Typically, concrete high-rise blocks constructed in the 1960s and 1970s were not protected against the ravages of our climate and pollution. As a result a substantial amount of structures of this sort have had their facades and steel reinforcement damaged by corrosion, allowing damp in and damaging concrete’s reputation in the process. The resultant necessary repairs mean that corrosion of steel in concrete has been estimated to cost the UK £550m a year overall. Since 1949 around 2,700 tower blocks have been built for housing in Greater London alone, so the scale of the potential problem is monumental.
Corrosion if left untreated
Unprotected concrete will eventually suffer the effects of carbonation and chlorination caused by rain and pollution, leading to deterioration of the façade which will allow water to ingress into the building fabric, endangering the steel reinforcement. Remedial action of patching a building with mortar, while an effective solution in itself, requires substantial and expensive scaffolding, the cost obviously increasing depending on the scale of the building. However this will not be the end of the expense, with numerous further repair works being inevitable sooner rather than later, meaning more scaffolding, installation costs and disruption to residents.
Applying a ‘band-aid’ to the problem in fact leads to more problems rather than solving them. Water can simply migrate to another spot within the building after the initial patching occurs, and building owners end up simply chasing corrosion across the building. Cost of repairs can also rise exponentially as water penetrates deeper into the structure. This all adds to an increased whole-life cost, where a more holistic preventative approach to protection could bring dividends, maximising and increasing the building’s service life.
Total Corrosion Management System from Sika
A ‘total corrosion management’ (TCM) solution means tackling the problems before they arise, with a single, but multi-faceted prevention strategy rather than endless attempts at cure which are only temporary solutions. Protecting concrete with a belt-and-braces anti-carbonation coating, for example, means that the rest of the structure is protected; it’s important to remember that we are talking about the ongoing health of the whole building fabric.
Sika’s TCM approach comprises a complete end-to-end system, starting with assessment, diagnosis and repair, but then moving on to applying advanced inhibitors such as FerroGard-903 and finally anti-carbonisation coatings to future-proof the structure. FerroGard-903 is applied to the exterior as a spray but it soaks in to form a protective layer around the steel reinforcement. Sika’s Galvashield is another innovative way to protect concrete, consisting of a galvanic anode made of cementitious mortar with a ‘sacrificial’ zinc core which attracts the corrosion away from the steel.
Although Sika is able to cater for clients that only have the budget to undertake short-term repairs to their structures, if you have a problem with carbonisation or chlorides entering their concrete, come and speak to us as we can offer a cost-effective longer term solution. As well as offering Total Corrosion Management, we are also the only company to be able to offer the full range of solutions, meaning we can address different corrosion requirements within one project. In addition this means we offer a joined-up expert approach, and a single point of contact.
Many specifiers and building owners are finding out the hard way that a piecemeal approach to dealing with corrosion can not only lead to significant ongoing hassle, but also increased costs down the line. By contrast, we can show you how a ‘total’ approach to preventing corrosion can offer a much more effective outcome, future-proofing your buildings.