Resin-based floor coatings, such as epoxy and polyurethane, are commonly used for industrial floors. Over time, this coating will need to be re-applied or removed, and a new resin coating applied multiple times to keep the floor in a good condition. Due to the robust nature of these coatings, removal can cause damage to the concrete, requiring specialist repairs to the surface.
Making new from old
An alternative to this cycle of re-applying floor coatings is to make a finished floor of the structural concrete through mechanical grinding, in several steps, using finer and finer diamond tools. The floor surface that is achieved has many beneficial properties, where economy, long service life, reduced environmental impact and easy maintenance are the most prominent.
Assuming that the quality and compressive strength of the existing floor will allow for refining to a polished concrete, there may be some elements of the project which may be impossible for your flooring contractor to influence.
Concrete is a natural material, which means that every concrete floor is unique. This is due to the infinite possible compositions of stone, sand, cement, water and additives. Below are some limitations and challenges that the owner or specifier should be aware of:
Do aesthetics matter?
When renovating an existing floor, the distribution of aggregate within the concrete cannot be changed. Once ground down, some areas may have more aggregate exposed than in others – as opposed to a new floor, where distribution may be more even and therefore more attractive.
Cracks and crazing
As water and heat escape during curing, a concrete slab may shrink and produce cracks. This can be controlled or minimised on new floors, but if the existing floor has cracks, you can grind away most surface or shrinkage cracks and repair the movement cracks by chasing them and inserting a flexible joint repair system. It should be noted that these do not affect the performance or function of the floor.
Air bubbles or voids within concrete may be exposed during the grinding process. These can be filled during the process for a more homogeneous appearance and does not affect the performance.
Where different batches of concrete have been used on the floor during the original installation, there may be colour variations. This doesn’t usually affect the performance of the floor and is purely aesthetic.
To avoid staining, it is possible to treat the finished concrete floor with a floor protection system. This depends on the application and may make a slight colour enhancement.
Concrete is produced using various forms of lime, which have a high pH value. Aggressive cleaning agents may attack the lime, so it is important to use Diamond cleaning pads or micro fibre mops on smaller floors and water only to maintain the gloss of a polished floor. Speak to your flooring specialist for advice.
Choosing polished concrete floors through refining of the structural concrete is a long-term solution for industrial applications, with downstream cost-savings for the facility. As with any flooring installation, being aware of the benefits and limitations is key to achieving a fit-for-purpose flooring solution.
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