Polished Concrete Floors
Introduction
Polished concrete floors provide an affordable alternative to expensive
floor treatments, with a wide range of colours and finished that
are comparable in terms of appearance, to those of tiles, vinyl
and cork. They are energy efficient and offer a low maintenance
and dust free floor.
The concept of a polished finish dates back some 20 to 30 years
and was originally used to describe the process whereby a typical
grey or coloured concrete floor was coated with a wax product and
then highly polished. The wax used was generally powdered beeswax.
The surface was then polished by rubbing vigorously with a soft
cloth, hence the term “polished concrete floors”.
These days while the name remains, the final surface finish can
be achieved in a variety of ways. Modern finishes such as liquid
polishes, latex coatings, chemical sealers, grinding (to expose
the aggregates), using colours and special aggregates to achieve
‘rock or marble’ type finishes are all economical ways
of achieving a variety of effects.
Polished concrete finishes have been generally associated with
slab-on-ground type construction. However with the variety of economical
concrete solutions currently available for suspended slabs, there
is no limit to the application of polished concrete floors.
Achieving the Surface Finish
Because of the ‘polished’ look of the surface a good
quality steel trowelled finish is usually required to the concrete
surface. However some people consider a few trowelling marks create
texture and add interest to the finish. Power trowelling by using
what is known as a ‘helicopter’ is the easiest way of
producing a very flat, even surface. This is best done prior to
the walls being built, and necessitates the protection of the slab
surface during subsequent construction.
Polished Exposed Aggregate Finish
To achieve this finish the surface of the slab is ground to remove
the cement paste, in order to expose the aggregate or stones within
the concrete or topping mix. The surface is then polished using
progressively finer grinding pads.
Usually because the cost of grinding or polishing is an additional
expense, special aggregates are often selected to achieve the best
appearance from this type of finish. Aggregate colours, types (round
or crushed), sizes, minerals etc can all be selected and blended
to achieve the desired effect. Two things need to be remembered:
the hard durable aggregates used in decorative concrete mixes will
increase the cost of grinding pads as they will wear faster. On
the other hand, fewer grades of pads (coarse to fine) are required
to produce a polished finish on a concrete slab. Overall, the cost
should still be less than that of a tiled finish to the slab, and
the possible effects can be stunning. Secondly, it is easier to
grind the slab prior to walls being built because there are no edges
or corners to worry about. In this case, protection of the surface
is required.
Sealing the Surface
The final process involved in a polished floor is the application
of a surface sealer. A range of options exist from wax-based products
to various other chemical sealers which give a durable, long-wearing
protective coating to the surface.
The skid resistance of polished concrete floors also needs to be
considered as the sealed surface can become slippery when wet. The
use of measures to provide skid resistance therefore overcomes any
problem using this finish outdoors.
Maintenance
Polished concrete floors are easy to maintain with only regular
cleaning required. The sealer prevents staining and should keep
the finish looking good for years.
Conclusion
The current trend towards a low maintenance and dust free (and hence
reduced dust mite) environment, produces a healthier living environment
generally. Polished concrete floors are an ideal low cost solution,
well suited to houses designed using passive solar design techniques.
To produce energy efficient housing, more and more people are utilising
the inherent benefits of concrete slabs.
As concrete slabs are a lifetime investment, long term durability
is also achieved. Whenever the finish starts looking a little dull,
recoating can easily restore the floor to its original appearance.
(FROM ‘BRIEFING 05 AUGUST 2001’
THE CEMENT AND CONCRETE ASSOCIATION OF AUSTRALIA)
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