Industry Information – Decorative Concrete – What should I know?

Decorative Concrete – What should I know?

The purpose of this guideline is to highlight the characteristics of decorative concrete and to avoid disappointment due to unrealistic expectations. All information should be considered, regardless of concrete supply company, plant location or installer or contractor used. This would include Coloured concrete, exposed aggregate, stamped concrete, honed concrete.

From an aesthetic perspective, the following points should be viewed as “characteristics” and not faults of decorative concrete.

There are a number of variables which will mean that no two decorative slabs look the same, specifically:

1. Concrete is made from natural raw materials.
2. Weather and site conditions.
3. Placing and curing methods.

Decorative concrete is not for everyone, a few things to consider.

  • Decorative slabs will exhibit uneven shading of aggregates and/or oxide, creating a look that may be referred to as “mottled or aged”.
  • A consistent hue or shade is impossible to achieve in decorative concrete. The use of polythene over the sub-base may reduce the incidence of mottling, especially on coloured slabs, as it provides a consistently dry sub-base and therefore more uniform curing.
  • The inconsistency of sunny/shady areas may mean that two pours of the same mix appear different.
  • All concrete slabs may at some time exhibit cracking in some form. Whilst there are several procedures which should be practised to lessen the likelihood of cracking, crack-free slabs cannot be guaranteed.
  • Trowel and screed marks may sometimes be visible.
  • The appearance of a decorative concrete slab will change significantly once acid washed and sealed.
  • A decorative concrete slab spanning from an internal area to an external area will appear different due to differing light conditions and reflection.

Sample discs on coloured concrete sample boards are small, and have been cast and not poured, therefore the mottling effect cannot be truly replicated in these samples. All samples, photographs and brochures should be used as an indication only and not a direct comparison.

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