There are two types of Polished Concrete
1. The first is a Mechanically Polished Concrete (MPC) and there are few other well known processes such as the HiPERFLOOR or Superfloor.
2. The second is a process known in the industry as a Grind and Seal.
There are advantages and disadvantages for both processes, which process you choose will depend on your application needs and budget.
Types of Polished Concrete
Perfect for indoor concrete, MPC is a more high end process involving up to 14 different steps to achieve the desired finish. This involves grinding and then grouting the concrete, hardening it with a densifier, giving it a high shine with a diamond impregnated resin, and finally using a sealer to prevent staining. The end result is a floor that looks and feels like glass. While this option is more expensive upfront, it requires much less maintenance and so is a cheaper option in the long run.
Grind and Seal, on the other hand, is cheaper initially, requiring far fewer steps to complete. After being ground, clear coats of sealer are applied to make the floor shiny. Unlike MPC, this process works well on both indoor and outdoor surfaces, and is great for pool areas and gardens. While it is the cheaper option, it will deteriorate over time, and the sealer will need to be sanded back and reapplied.
Both MPC and Grind and Seal polished floors can be supplied with different levels of exposure, depending on how much stone you would like to show on the surface. You can select from nil-exposure, minimal exposure, or full exposure.
MPC – The Process
In this concrete polishing process the floor is generally ground twice depending on whether you are after the minimal or full exposure look then it’s grouted to fill in pin holes and small cracks, we then put a densifier down to harden the floors surface by up to 10 times and go over the floor up to 7 times with diamond impregnated resin pads to get the desired shine (the concrete itself shines, there is no artificial shine from topical sealer and therefore the coating does not scratch off), then the floor receives a penetrating sealer which soaks into the floor to prevent staining which leaves the floor looking and feeling like glass. This high end process has between 10 & 14 steps but is suitable for indoor concrete only.
MPC – The Cost
MPC (Mechanically Polished Concrete) is more expensive upfront, however it is the cheapest flooring solution available over the life of the floor. Residential floors range from $100 to $120 per m² + GST, Commercial floors (MPC) ranges from $75 – $110 per m2 + GST*
*price varies due to the amount of stone/aggregate exposure (minimal or full) and gloss level matte/semi-gloss or high-gloss required also the condition of the floor is taken in to consideration. For smaller areas under 30m² prices are given after viewing the floor, however there is a minimum call out of $3,600 plus GST for MPC.
Grind and Seal – The Process
In this process the floor is generally ground twice depending whether you are going for the minimal or the full exposure look (how much stone you want to be able to see). Then the floor can be grouted (70%-90% of pin holes and cracks are filled) then 2 coats of sealer are applied which sits on the surface, giving the concrete a shiny appearance. There is between 3 & 5 steps in this process and it is suitable for indoor and outdoor concrete. One advantage of this process is that you are able to put some grit into the sealer in order to make it anti-slip. This great for areas around pools and in back yards. Like all sealers though there will come a time where the sealer will need to be sanded back and re-applied.
Grind and Seal – The Cost
A Grind and Seal is cheaper initially, however due to the fact that the top layer is a coating, and like any topical coating will deteriorate over time due to foot traffic, eventually will need to be re-coated or possibly sanded back and re-coated. Grind and Seals range from $55 to $75 per m² +GST*.
*price varies due to the amount of stone/aggregate exposure (minimal or full), if grouting is required and also the floors condition is taken in to consideration. For small areas there is a minimum call out of $2,800 + GST.
Grouting for Polished Concrete
This is a polishing procedure where we put down a latex based product on the floor in front of the concrete grinder and mix it with the concrete dust from the grinding procedure so the colour. This creates a slurry paste which is pushed into the pitted areas of the surface and fills in all the tiny little pin holes/ripples in the concrete which gives the floor a smooth/flat/shinny appearance. This procedure is always done for mechanically polished concrete and is optional for grind and seals.
Polished Concrete Exposure
For both types of polished concrete you can select your level of aggregate exposure that you want to see. There are some circumstances where the concrete is too soft for minimal exposure. The levels are commonly known as
• Nil Exposure – light burnish – Very little to no stone shows on the surface of the concrete (this is difficult to achieve unless the concrete has been poured perfectly)
• Minimal/random exposure – This is where there is small amounts of stone visible on the surface – some areas may have no exposure and some may have heavy. This is also referred to as a salt and pepper look and is achieved by just a light grind – approx 1-2mm from surface.
• Full exposure – this is where you can see all the stones on the surface and requires a heavy grind – usually approx 5ml below the surface.