Decorative concrete has become a main contender as a material of choice for designers and homeowners, not only because it provides one of the most permanent floorcoverings, but its versatility can be expressed in stained, coloured, painted, polished, stamped and personalised floors which are now regularly seen in retail stores, restaurants, offices and homes everywhere.
Concrete flooring no longer has to be grey and boring. Colouring concrete or applying textures, patterns and saw cuts can bring new life to this traditional substrate. Concrete can be so uniquely designed or so naturally coloured that it blends seamlessly with other elements in a room and often it is not recognised as a concrete floor.
Concrete floors are easy to maintain, are a good alternative to floorcoverings that may provoke allergies, and are very easy to keep clean. They are particularly beneficial if the property is subsequently sold, because the new owner can use the existing floor as the base for a different finish such as carpet or tiles if the polished or coloured concrete floor is not preferred.
Staining concrete is one of the most popular applications for transforming concrete slabs, and homeowners, architects, interior designers and builders often favour stained concrete because of the unique effects that can be achieved by combining colours and application techniques on the cement flooring.
Using acid-based chemical stains, decorative concrete contractors have been able to achieve rich, earth-toned colour schemes resembling natural stone, marble, wood, or even leather, giving a completely custom look to cement floors, concrete driveways, patios, walkways, pool decks and more.
Most acid stains are a mixture of water, hydrochloric acid, and acid-soluble metallic salts. They work by penetrating the surface and reacting chemically with the hydrated lime (calcium hydroxide) in the concrete.
The acid in the stain lightly etches the surface, allowing the metallic salts to penetrate more easily. Once the stain reacts, it becomes a permanent part of the concrete and won’t fade, chip off, or peel away. Acid-based stains are translucent and the colour they produce will depend on the colour and condition of the substrate to which they are applied, making each floor a unique feature.
The downside of acid stains is that they don’t offer a broad colour selection, being mostly available in a limited range of subtle earth tones (tans, browns, terracottas and soft blue-greens), but some products such as water-based penetrating stains and water- and solvent-based concrete dyes are able to provide colours ranging from soft pastels to vivid reds, oranges, yellows, and purples.
The effect is a natural-looking colour pattern with mottled shades of the same hue. This concrete flooring finish looks classy in new homes, and it is very easy to maintain. Obviously floors can also be painted, and there is a wide variety of paint options available in South Africa.
Apart from acid staining, concrete can be coloured with colour hardener, integral liquid or powder, to name a few. The process of integrally colouring the concrete offers the advantage of the entire volume being coloured. Dry-shake colour hardener is another popular way to colour concrete but, although the concrete surface then obtains a longer wear life, its strength is not increased.
This is another popular trend that can have a dramatic effect on interior floors as well as outdoor areas such as patios and lapas. Stamped concrete is concrete that is patterned and/or textured or embossed to resemble brick, slate, flagstone, stone, tile, wood, and various other patterns and textures.
The ability of stamped concrete to resemble other building materials makes it a less expensive alternative to using the authentic materials.
There are three procedures used in stamped concrete which separate it from other concrete products: the addition of a base colour; the addition of an accent colour; and stamping a pattern into the concrete to produce the final desired result.
The accent colour is the secondary colour used to produce texture and show additional features (e.g. grout) in the stamped concrete. The accent colour is produced by applying colour release to the concrete, and this has two purposes: it is a pigment used to colour the concrete and is also a non-adhesive used to prevent the concrete stamps from sticking to the concrete.
Cast-on colour release can be used, and this is a procedure where the powder colour release is applied by spreading it on the surface of the concrete before the concrete is stamped. Another procedure can be provided by spraying a liquid colour release on the bottom of the concrete stamps before the concrete is stamped.
Concrete stamping is the procedure which provides the pattern in the concrete. Concrete stamps are placed on the concrete after the colour release has been applied, and are pushed into the concrete and then removed to leave the pattern in surface of the concrete.
Epoxy floors and concrete overlays
One of the most effective and least expensive ways of colouring an existing concrete floor is by using a polymer coating or overlay – pouring a layer of tinted polymer over the existing floor to add colour and design.
Chemically resistant, these seamless floors are made of epoxy and urethanes that are also resistant to dirt and stains, and impervious to water, and these flow-coated surfaces stick to the flooring surface without chipping, peeling, or lifting. With good preparation, they provide a permanent surface that requires little or no maintenance.
Using polymer coatings, floors can be made to look like other surfaces such as granite, tile, or slate. Logos, stripes, and even floors with an integral ‘sparkle’ are now appearing in restaurants, garages, basements, as well as upmarket homes.
Polishing Concrete Floors
Polished concrete is fast becoming a highly desirable flooring material. The recent advances in polishing equipment and techniques mean that contractors are now grinding concrete floor surfaces, new or old, to a high-gloss finish that never needs waxing or coating.
Retail, warehouse and office facilities now often have polished concrete floors in preference to hard floorcoverings, and architects and homeowners are regularly using these smooth, high-lustre floors that can replicate the look of polished stone for even the most upmarket residences.
To polish the concrete, heavy-duty polishing machines equipped with progressively finer grits of diamond-impregnated segments or discs (similar to sandpaper) are used to gradually grind down surfaces to the desired degree of shine and smoothness.
Almost any structurally sound concrete floor, new or old, can be polished, but there are some exceptions. Floors that are uneven, need extensive patching, or that are extremely porous may not be good candidates for polishing, but an experienced contractor can usually determine the suitability of the floor.
There are numerous options available with polished concrete, including coloured aggregate or glass, which can be applied to the concrete mix or seeded into the top layer of the mix to become revealed by the polishing process. Integrally coloured concrete can also be used.
Concrete flooring provides so many options for any commercial or home application, both indoors and out. With bold styles and colours and relatively low maintenance, it is no wonder concrete flooring has become a major design trend today.
Acknowledgement and thanks are given to the following for information used in the compilation of this article: www.cnci.org.za; www.acidstain.com; www.concretenetwork.com.