Colour in concrete

Giving concrete a colour facelift OR 5 ways to colour concrete.

Whether you operate in the professional arena of architecture and building or play in the DIY space, concrete is one of the most versatile materials. Don’t be fooled. Behind the age-old grey of concrete is colour application that can breathe originality and longevity into any exterior or interior design. Here are five concrete colouring techniques to bring your concrete areas or designs to life.

Number: 1

Integral colouring

As one of the more popular ways to colour fresh concrete, this approach brings liquid or powder colourants together with the concrete during the materials mixing process. As a result, a uniform colour is created for a concrete slab or structure. It stands to reason that this technique is often used for large monochrome areas, and particularly areas where the look of natural stone needs to be replicated. The big benefit of integral colouring is that the process of the admixture infusing with the concrete generates consistent and fade-resistant colour.

Number: 2

Shake-on colour

Dry-shake colour hardeners are powders that are literally shaken onto fresh concrete and worked into the surface with a trowel. Hardeners colour the top surface layer of concrete, making the colour more intense than if integral colouring was applied. The approach enables application of one or more accent colours. It is often the choice for colouring exterior slabs exposed to freeze-thaw conditions and for heavy foot traffic areas because hardeners improve the strength and density of the concrete surface. Shake-on colour though must include a note of caution. Grinding and polishing concrete colour-treated in this way removes the colour. Added to that, the powder can be harmful if inhaled.

Number: 3

Concrete staining

Concrete staining can be done using acid-based chemicals or water-based acrylics. Staining using acid-based chemicals gives a plain concrete floor a deep richness in earthy tones of browns, tans and tepid blue-greens. Stains can infuse a concrete surface with translucent, shimmering tones, and can render results that mirror anything from tanned leather to natural stone or polished marble. This technique can even create the look of stained wood. One of the benefits of concrete staining is that the effect becomes a permanent part of the concrete and won't chip off, fade or peel away. It is also handy that both acid-based chemicals and water-based acrylics can be used on new or old, plain or integrally coloured concrete.

Number: 4

Concrete dyes

More and more, concrete dyes being used to boost color palettes. Not only do they dry quickly but they are safe, odorless and easy to apply. They are also versatile as different colours can easily be ‘mixed and matched’ from a palette that includes reds, yellows, oranges, purples and blues. One of the more beautiful effects that dyes can create when hardened, densified and polished are a gemlike appearance. Though it must be remembered that dyes tend to have some transparency. They will not mask an underlying colour or disguise flaws in an existing surface and may also fade when exposed to direct sunlight.

Number: 5

Colour hardener/densifiers

The use of a colour hardener/densifier is a convenience booster in colouring concrete. This technique enables you to harden/densify and colour in just one step. If you need to apply color hardener/densifiers to concrete floors ground no finer than with a 200-grit resin pad, this is the approach to consider. In short, fine colour pigments suspended in water are blended by the applicator with a lithium-silicate hardener/densifier. Just take note that similar to shake-on colours, this treatment is a surface-based treatment and as a result, polishing will remove colour.

Written by Sephaku Cement.