Fixes for Common Concrete Surface Color Problems

Unfortunately, complaints about how color turns out are an all-too-familiar topic of conversation. Complaints can involve but are not limited to integrally colored concrete, color-hardened concrete, stamped and textured concrete and stained concrete. People claim the wrong color, inconsistent color, blotchy color, color that is too light, color that’s too dark, and the list goes on and on. When you really think about it, it does make sense. What is the biggest difference that separates decorative concrete from regular concrete? Color!

I have often found that when a gray sidewalk, patio or driveway is poured, you can have multiple tones of gray, discoloration and blotchiness and no one takes a second glance. Add a small amount of color to the very same pour, and even the smallest color differences have ended up in a courtroom at a cost of thousands of dollars.

So, with the understanding that surface color issues will occur no matter how well a job is planned and or executed, let’s look at some popular and successful remedies for correcting these color problems.

Without fail, the call comes at the worst possible time. “The color is wrong,” states the voice on the other end, with the confidence and understanding that color in concrete is a sure thing, just like paint from a can. After the complaint is researched, it is determined that something, somewhere along the line went haywire. The concrete is structurally sound, but indeed the color is some fashion of wrong. The customer can’t or won’t live with it, so what are you going to do about it?

STOP! Before we go any further, let me interject. At this time in our little make-believe scenario, salvaging the job and making money or losing money hangs in the balance. If you discussed with your clients in advance (and put in writing) the possibility of color variation and how it can occur due to the natural variations of raw materials found in concrete, you are way ahead of the game. This is called managing expectations, and if you have read any of my previous columns you know I am a huge advocate. If you did not discuss these possibilities, experience has shown you are in a bad place and chances are that you are going to end up getting stuck with some or all of the repair bill. No matter how your customer’s expectations were managed, stay calm and communicate that this can be fixed — and don’t ever say, “I have never seen this before.” That statement does not instill confidence in your ability to resolve the issue.

When dealing with surface color issues, the type of repair is going to be determined by a few key factors.

What is the final look you are after? For example, the solid-color look of integrally colored concrete or the natural-stone look of stamped concrete?

How big is the repair — small random spots or a thousand square feet of continuous slab?

What type of performance is expected? No repair is as good as the original. What type of maintenance is acceptable?

The following is an overview of the most common and successful repair products and systems for surface color issues that I have worked with over the last 15 years.

Translucent penetrating stains: This family of stains produces a color tone that ranges from a very light color wash to semiopaque. These types of stains work best on less severe surface color issues (minor blotchiness, minor discoloration and minor surface contamination) where significant hide of the underlying color is not required. They also work well where some level of marbling or variegation is desired. The most common of these products are acid stains, water- and alcohol-based acrylic stains and dyes. The biggest limitation is their need to penetrate, which means the surface being repaired needs to be free of all sealers and coatings.

Solid-color penetrating stains: Unlike their translucent cousins, solid-color stains provide 100 percent hide and are opaque. They are the desired fix for more severe color issues where full coverage and hide is required. The most common of these problems include discoloration from curing blankets, faded or severely washed-out color, and batch-to-batch color inconsistency. Once again, the biggest limitation is their need to penetrate, which means the surface being repaired needs to be free of all sealers and coatings.

Tinted or colored sealers: This method of coloring concrete differs from stains in that the color is contained in a film or membrane. They can range from very translucent to opaque. Colored sealers are often used for repairs where a sealer already exists, eliminating the ability to use penetrating stains. Depending on the product used, they can be applied almost immediately after the concrete is placed and tend to have a lower price point compared to other repair products.

Highlighting tints and washes: These products are used specifically for repair of stamped or textured concrete. They all work on the same principle. A nonreactive colorant is suspended in a liquid carrier — most often water. When applied to textured or stamped concrete, the “colored water” seeks the low areas of the surface, concentrating color in those areas. The carrier (water) evaporates, leaving the color behind. These color washes have no bond to the concrete and require a sealer to lock them into place. Their biggest limitation is lack of depth of color. They are designed to change or further accent highlights, not change the overall color of the concrete. Overapplication can result in excess color acting as a bond breaker when the sealer is applied.

Toppings: The nuclear option when a stain or colored sealer will not work is a topping. When the color or surface are so bad that a new concrete surface is required, microtoppings are the option of last resort. These thin polymer-modified coatings are typically used when the concrete is damaged or contaminated to a point where stains or colored sealers will not work. Graffiti, construction paint, oil and grease are the most common of these contaminants. The biggest limitation would be the amount of preparation required prior to application, as the surface needs to have a certain profile for proper adhesion. They also tend to be expensive when compared to the other options.

It’s never good when problems occur, but armed with these repair options, you now have the ability to solve the problem, satisfy the customer and save your paycheck.

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