How to Make Polished Concrete Floors, Part 1

by Chris Lang on February 14, 2012

How to Make Polished Concrete Floors

Polished concrete is a relatively new flooring finish that is gaining in popularity here in Australia and across the globe. As a finish that was only seen in chic inner city cafes, polished concrete is becoming more common in residential home applications. Upon closer investigation, the reasons for this are obvious. Polished concrete provides an amazing array of effects, is hardwearing, cost effective and easy to keep clean and looking good for years. Polished concrete is also a sustainable choice. In this article, Luke provides an insight into the options available when considering polished concrete and also considerations for ensuring the best results.

Why choose polished concrete?

Think sustainable flooring and you may think of recycled Baltic pine or even compressed bamboo floor boards. If you are considering building a new home or renovating an existing home on a concrete slab, then polished concrete is worth considering. Concrete is considered a low embodied energy building product meaning that it takes a relatively low amount of energy to manufacture and transport per kilogram.

In addition, concrete is a great source of thermal mass, helping to keep a home warmer in winter and cooler in summer. Our own home demonstrates this. During the heatwave that hit Victoria in early February 2009, the inside of our home remained at 26 degrees whilst it reached 46 degrees outside. This was achieved without any form of air conditioning although double glazed windows and good wall and roof insulation helped.

A polished concrete finish also provides an opportunity to add in slab hydronic heating. There is nothing better than returning home from a cold winter’s day and feeling that deep penetrating warmth radiating from the floor through your socks.

Pouring the slab
Pictured: Pouring the slab over hydronic heating pipes

Polished concrete is also a good flooring option for people with allergies. It does not harbour dust mites and other allergens, and is easy to keep clean. A light mop once a week is all that is needed to keep it looking good. It resists staining and is very hard wearing, although this is dependant upon the type of finish you use.

For existing and new homes

A polished concrete floor can be adapted to either existing or new homes, whether they are founded on a concrete slab or not. The most straightforward approach is to polish the slab of a new home before frame erection commences. This means that a consistent result is achieved across all rooms and that internal corners are not left unground and unpolished.

If you are worried about scratching the floor surface during the construction of your home, you can protect it with particleboard or alternatively just complete the grind and grouting process before the frame goes up (more on this shortly). In our experience though, protection is not really necessary if you opt for a polished, rather than a sealed finish. In building our home, we got the slab polished using the HIPERFLOOR system before the frame was erected. The floor did not scratch or wear throughout the entire construction process.

Polished Concrete Floor
Pictured: Concrete HIPERFLOOR high gloss finish and quartz stones

If you are looking to retrofit a polished concrete floor to an existing home, there are a few options to consider. Obviously the most cost effective option would be to grind and polish back an existing slab. But what if the slab is cracked or uneven or you are looking to add some personal touches like colouring the concrete? In this case, you could pour a float concrete over the existing concrete floor. This is sometimes termed over-pouring.

In addition, self-levelling pours are becoming more common as they are quicker and easier to install, and consist of compounds mixed with concrete to give a free flowing consistency that naturally finds its own level. Alternatively, you may like to consider more of a terrazzo finish, where stone chips are typically set in a coloured epoxy resin. A terrazzo finish is light enough to be applied on top of existing timber flooring and is ideally suited to indoor applications only.

Making it personal

A polished concrete floor is like a blank canvas. You can create almost any effect that you can imagine. Here are some features that I have had some experience with that you may like to consider in creating your own polished concrete floor:

Colouring the concrete. There is a vast array of concrete pigments available, some surprisingly more expensive than others. If cost is important to you, then be prepared to be a little flexible on the colour you choose. A slight change in shade could save you thousands.

Seeding the slab with:

  • Decorative stones and stone chips – select these no bigger than a closed fist. They are likely to dislodge during the grinding and polishing process if they are any larger.
  • Shells. Best results are achieved when they are sliced lengthways and they are less likely to collect air pockets that once ground back need to be filled later.
  • Marbles and glass beads. These can provide an amazing effect once ground back.
  • Steel strips and tubes. A non-corrosive metal, like stainless steel or brass works best.

Polished Concrete Floor
Pictured: Concrete HIPERFLOOR high gloss finish showing quartz and blue glass bead

Seeding is the process where materials are scattered over the surface of slab just after the initial screed, and then lightly bull floated so that they are pressed in just below the surface.

These are by no means the only options. Anything that is hard and that can be stuck in concrete can ground back to produce interesting results.

To be continued – stay tuned for Part 2 of “How to Make Polished Concrete Floors” series.

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Written by Luke Potter

Luke is a writer and commentator on sustainable building and living techniques. At www.budgereehouse.com, you will find more information on how to design, prepare for, install and operate your own hydronic heating system.

{ 2 comments… read them below or add one }

Delia June 9, 2012 at 9:13 pm

Hi,
I am considering buying a house with hydronic heating under a polished concrete floor. Love the house. Very sustainable living. Solar, tanks, orchards etc. However there are some unsightly cracks beginning in the concrete which a neighbours says was only laid 18 months ago. Can these be succesfully repaired for cosmetic reasons. Any idea of the cost involved?
House is in Eltham, Vic.

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ultimatefloors January 22, 2015 at 4:03 pm

Concrete could be a nice supply of thermal mass, serving to to stay a home hotter in winter and cooler in summer.Polished concrete is additionally a decent flooring possibility for individuals with allergies. It doesn’t harbour dirt mites and alternative allergens, and is straightforward to stay clean.

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