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Color Clashes

0If you don’t prepare your clients for what will almost certainly happen to the appearance of this flashy form of decking and coping, writesPaolo Benedetti, you can find yourself facing unpleasant consequences — from encounters with peevish homeowners to meetings with their attorney.

It’s a simple, underappreciated fact: The placing of concrete is both a physical and a chemical process, and while the physical application and finishing of the concrete can more or less be mechanically replicated, the chemical process involves so many variables that accurate replication is virtually impossible.

The upshot of this is that, unlike matching a paint chip, matching a concrete sample for color is beyond the control of the contractor.

As a consequence, color matching cannot reasonably be expected – a point raised by responsible suppliers of concrete colorants in their promotional and technical materials. Yet despite these ample disclaimers, at least once a year I am retained to represent a party involved in a dispute over the final color of an expanse of decorative concrete.


Let’s start by looking at the set of variables hinted at above – with apologies for its length:

q Temperature (which affects moisture evaporation and set times)
q Exposure to direct sunlight while curing and beyond
q Time spent in shade while curing and beyond
q Exposure to wind while curing
q The moisture content of the concrete (not just mix water, but also the moisture contributed by added ingredients, including sand, rock and various aggregates and admixtures)
q Transit time for the ready-mix trucks (traffic delays being a crucial factor)
q The size of the ready-mix batch
q The number of revolutions of the mixer in transit
q The color of the base materials (including the degree of grayness of the raw cement powder)
q The choice between liquid or powdered coloring agents
q The choice between white or gray cement
q The use of admixes (water reducers, plasticizers, decorative aggregates and more)
q The appearance of minerals and/or chemicals in the mix water
q The pressure applied during troweling
q The use of curing compounds
q The curing method.

I could go on and on about how each of these can or will contribute to variations in concrete color, but that’s not really necessary – especially when you consider the additional fact that there are overarching timing factors involved as well, including the time of day in which events take place. It’s complicated, in other words – and we can all take it on faith that one or more of these factors will conspire to cause color variations.

So any concrete color sample, whether it’s a factory-supplied concrete coupon or a printed color chip, is no more than a generalization of the color that will develop on site. It is essentially impossible to exactly match them up.

Temperature is a huge factor in all of this, perhaps the biggest and most unavoidable of all, followed closely by sun/shade issues. You might gain some short-term control here by tenting the job site and holding temperature and humidity within that space to a narrow range for a while, but that’s a rare and temporary advantage – and it’s also where you learn that there are at least a dozen other factors that get in the way of a good, predictable color match.


This is why education is so important, right from the start. Architects, landscape architects, general contractors or other specifiers need to understand, along with the property’s owner, that despite the fact every effort is being made to control the variables, there’s only so much that can be done.


In this case, sun exposure has caused the top surface of a colored-concrete coping to fade over time – in contrast to the vertical face, which has faded less because its exposure hasn’t been nearly as steady. It’s an expectable contrast, but if the homeowner isn’t prepared for it to develop, trouble may result.

This is why we at Aquatic Technology Pool & Spa (Morgan Hill, Calif.) offer the following guarantee with our decorative, colored-concrete contracts: “The concrete will harden and crack; the color will not match the sample; the color will vary from one area to another; and, finally, nobody will steal it without making a lot of noise.” (Seriously, we find that a bit of levity drives the point home.)

We do all we can to prepare our clients and colleagues for the inevitability of the variations. We explain in detail that the color of the concrete will lighten over time as it is exposed to ultraviolet solar radiation and normal wear – and that surfaces in well-shaded areas exposed to less sunlight (against the house, under arbors, on the north side of an object or structure, under potted plants or beneath a barbecue) will retain the original color for a longer period.

We also draw as many relevant analogies as we can based on what we see in and around the house. The homeowners know that outdoor umbrellas as well as interior carpets, fabrics and draperies fade from UV exposure; they expect this and never complain about it – so why would they turn around and expect concrete contractors to offer a guarantee against any such changes?


Here, the colored concrete in the shaded areas behind the raised spa will keep their color intensity longer than the exposed area with its charming plastic lids. If the expectation was to align the concrete color with the tile treatment for the long haul, the homeowner will be disappointed before long and a call to an attorney may result.

To be sure, concrete’s apparent permanence is a factor here: Something so solid and weighty would seem immune to deterioration of any kind, the thinking goes – which is why we spend so much time relieving clients and colleagues of the assumption of eternal stasis.

As the concrete continues to cure and harden, we tell them, the color will lighten. We also suggest anticipating the change: If they have any doubt about the final color they’ll receive, it’s best to start with a darker shade that will hit the right levels months or years later.

You catch my drift: It’s all about establishing reasonable expectations and managing responses to the changes that will inevitably occur.


This educational part of the process takes patience and persistence: We sit down with the design team and/or the clients and explain that significant color variations will be visible throughout the applied, colored surface and that this is not only normal but expected. And we stress the fact that color variations on their own are not considered construction defects while pointing out that even small mock-up samples will vary from the hoped-for final colors.

Next – as suggested above – we put all of this in writing, having a responsible party sign a disclaimer we present that indicates we cannot match any color samples and further declares that we make no guarantees relative to color matching, color consistency or color variations.

There are millions of colored concrete projects in existence, and a surprisingly large number of them have resulted in disagreements and even lawsuits over their final colors. Don’t join that statistical pool! Come to an agreement with your clients and colleagues before the concrete is placed and do what it takes to avoid hearing the words, “You never told me” or “You never said that.”

Be honest and keep them honest: That’s a good two-way street.

Paolo Benedetti is principal at Aquatic Technology Pool & Spa, a design/build firm based in Morgan Hill, Calif. He may be reached at [email protected].

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