A popular home design trend of recent years has been the industrial look, where raw industrial elements (think exposed brick walls, large open windows and metal bars and poles) are combined with modern features (such as neutral colours, open floor plans and natural light) to create a fresh, simplistic look.
Polished concrete floors, online renovation and design community Houzz said, have featured heavily within homes that have embraced this trend, and are now available in a number of colours and finishes to suit a variety of homes.
So, what exactly are polished concrete floors, what types are available, and what costs are involved if you want to install this flooring in your home?
Let’s ‘pour’ over some essential facts about polished concrete, slab by slab.
What are polished concrete floors?
According to Cement Concrete and Aggregates Australia (CCAA), a peak body for heavy construction materials, polished concrete is a generic term to describe decorative concrete flooring options which leave the concrete surface exposed as the final floor finish. The CCAA state that polished concrete floors are affordable, energy-efficient, low-maintenance and dust-free.
CCAA’s Product Application Engineer, John Nichols, told Canstar that the expression “polished concrete floor” was originally used to describe the process whereby a concrete floor was coated with a translucent wax product, then polished by hand with a soft cloth to produce a fine finish with high gloss. However, Mr Nichols said a polished concrete floor has now evolved to mean any concrete floor surface that is smooth or glossy in texture.
Polished finishes, the CCAA state, can be achieved through a variety of techniques, which can create different colours and patterns in the floor. These finishes can be completed on concrete slabs that are either on the ground or suspended (such as a floor on the upper storey of a house).
How much does it cost to polish concrete?
According to online tasking platform ServiceSeeking, polished concrete installation carries an average price tag of approximately $50 per square metre, though the total cost will depend on a number of factors including the type of finish you choose. ServiceSeeking said for larger, more complex jobs, the rate could go up to $100/m2, whereas the cheapest quoted price on their platform in 2019 was $25/m2.
Types of polished concrete
Mr Nichols states that there are three basic methods of producing a polished concrete floor. These can be used to polish the concrete slab itself or to achieve a different look by using different materials in the top layer.
1. Steel trowelling
This is when a hand trowel (a small tool used for spreading and levelling concrete) is used on a partially set concrete slab (still wet) in order to work the cement sand around and create a fine finish with a “semi-shine”. The concrete can have marks from the trowel left in or out, depending on your preference as a homeowner. This method is generally used when a basic flat, smooth finish is required.
A burnished finish can be produced by applying waxes, liquid polishes and resin-based coatings to a partially set concrete surface, and then using a mechanical powered trowel (also called a helicopter) to repeatedly work the cement around to produce a “burnt” appearance which is then sealed in with an oil-based or acrylic sealer.
As burnishing tends to highlight even minor variations in the flatness or surface finish of the concrete, it is recommended that all flooring is even with no marks before this process can begin.
Mr Nichols said both a steel trowelled and burnished finish require a high degree of labour, as the surface must be worked around quickly to create the desired finish before the concrete hardens. It is for that reason that Mr Nichols said these two methods for producing a polished floor are now uncommon.
3. Mechanical grinding
According to Mr Nichols, the most common method today for producing a polished concrete floor is through mechanical grinding. This is done by allowing the concrete to set hard and then using grinding pads (on a grinding machine) to grind down the floor to produce a desired finish. Mr Nichols said there are typically two types of finishes you can get from a mechanically ground concrete floor. They are:
- Honed finish: This is produced by partially grinding down the surface with course and medium grinding pads to reveal a smooth matt finish. This finish will have a higher skid resistance compared to a gloss texture and may be suitable for outdoor floors or those that experience high foot traffic.
- Polished finish: This high gloss shiny finish is produced by fully grinding the surface with progressively finer grinding pads and is generally suitable for indoor flooring surfaces.
The process of grinding the concrete will expose the aggregates (materials in the concrete such as sand, gravel and stone) which can provide different patterns and colours. A sealer is then applied and absorbed into the concrete to help prevent staining, keep the concrete surface looking good and to facilitate cleaning.
How are polished concrete floors installed?
Build.com.au, an online building and renovation publication, said a concrete floor can be laid either as part of the foundation slab or as a cap (or topping) overlaid on an existing concrete floor.
Once the concrete is poured, then one of the above methods will be used to provide the polished finish. The concreter will need to know what method you are using while laying the slab, to ensure they can give it the type of finish you’ve chosen.
The CCAA states that colours can be introduced to polished concrete floors by adding pigments to the concrete when mixing it, or by applying aggregates, chemical stains or dyes and tints to the surface. It also advises that patterns can be created by saw-cutting pattern lines into the surface, using different joints, or adding aggregates when polishing.
Existing concrete slabs can also be polished, according to the CCAA, but this will depend on their condition. Some surface preparation, such as the removal of minor defects or trowelling marks, may be required on existing floors before polishing can begin.
How long does concrete polishing take to complete?
Online service directory hipages states that the time it will take to polish concrete in a home will ultimately depend on the size and complexity of the project, but could take upwards of two to three days.
What factors influence the price of polished concrete?
The cost to install polished concrete floors in your home could differ depending on a variety of factors. According to ServiceSeeking, these factors may include:
The size of the floor
This is usually measured per square metre, or sometimes by square foot. Generally, the smaller the size of the floor, the cheaper it is to polish it.
The floor’s current condition
If you are polishing an existing concrete slab that has cracks or blemishes, you may have to spend extra money to have those issues repaired before polishing can begin. If the slab needs to be resurfaced, this will generally come at an extra expense.
The method used to polish the floor
Generally, mechanically polished concrete which is fully ground down to give the highest level of gloss to the surface, is the most expensive method to polishing concrete. Mechanically polished floors typically last longer and are more durable than other types of polished concrete while also being aesthetically pleasing.
The level of polish required
The more polished you want your floor to be, the more grinding or burnishing required. This may require more labour and add to the overall project cost.
The floor design you choose
A variety of colours, textures and patterns can be added to polished concrete floors, however these may come at an additional cost.
The complexity of the job
You can typically expect to pay more if you are polishing concrete surfaces that are irregularly shaped, sloping or circular, as these types of surfaces are generally more labour-intensive.
Benefits and downsides
If you are planning on installing a polished concrete floor in your home, you may want to consider some of the following pros and cons before you commit.
According to Mr Nichols, polished concrete floors are the most durable floor in the housing industry. “They will not be eaten by termites, will not rot from moisture, will not burn if exposed to heart or flame, will not wear out, and will outlast many generations of the people that live in the house,” he said.
- Hold’s heat from sunlight
Houzz states that concrete floors can work as a “thermal mass” if they’re exposed to the sun, meaning they can absorb and store the heat of direct sunlight and slowly release it over the day and into the night. This internal heating, it says, could make a difference to the comfort of your home and potentially to your utility bills come winter time.
- Variety of colours, patterns and textures available
Polished concrete can come in an array of different design options, and made to match many styles, according to hipages.
The CCAA states that polished concrete surfaces are easy to maintain, and regular mopping is generally all that is required. However, Build.com.au does state that re-waxing every three to four years is also recommended for some polished floors in order to maintain the protective layer over the surface.
- Cold surface
The surface can feel cold if it is not exposed to much sunlight, meaning they aren’t necessarily ideal for colder climates. However, a good-quality rug can help warm up areas if necessary.
- Hard and unforgiving
Hipages states that because these floors have no give, they can be uncomfortable for some people and hard on the knees and other joints. They can also be unforgiving if glass or other fragile items are dropped onto the floor.
- Susceptible to moisture
Houzz reports that although polished concrete can be waterproofed, moisture can still make its way up from the ground if the floor is not properly sealed on both the top and bottom surfaces. It warns this can lead to the growth of visible mould or mildew, which may impact the structural integrity of the slab and can be costly to fix.
Looking online or visiting a showroom may help you visualise how polished concrete would look in your home and give you more information about the options and pricing for this type of flooring. For further guidance, you may find it helpful to get in touch with a flooring professional.
Cover image source: Waclaw_EPI (Shutterstock)