Concrete Staining

Since its inception, PaintPRO’s mission has been to offer timely, useful information on new products, innovative techniques and emerging trends that affect the nation’s painting contractors. One such emerging trend is the demand for decorative concrete — stained, colored, textured — in both commercial and residential markets, for interior and exterior applications alike.

In our February 2000 issue, we provided an introductory overview of the concrete stains market, followed by an article on concrete surface preparation in our February 2001 issue. The response has been overwhelming. In fact, the interest it sparked resulted in the introduction of our sister publication, Concrete Decor, which focuses exclusively on the decorative concrete marketplace.

For painting contractors, decorative concrete projects offer an excellent opportunity to expand their business beyond the traditional markets. Those who are willing to make a small investment in tools and training can assure themselves of a lucrative, even enjoyable way to gain added business, using many of the skills and tools they already possess.

Within the past several years, demand for decorative concrete has grown almost exponentially. Initially favored by commercial establishments such as casinos and hotels, architects and designers have come to realize that enhanced concrete — stained, colored, textured — has become an attractive option in residential applications as well, both interior and exterior. Concrete — long regarded as a sturdy, durable, functional construction material — is also viewed as dull, gray, and boring. However, thanks to an ever-widening array of products and techniques available from dozens of manufacturers, concrete surfaces can now be aesthetically pleasing, distinctive, unique, eye-catching works of art.

“Adding color or texture to concrete really completes a project and provides a certain mood or ambience,” says Steve Darke, Southwest regional sales manager for QC Construction Products. “Unless you’re getting extremely intricate and calling for time-intensive designs, the cost of adding decorative color is negligible, and the result is well worth it.”

Painting contractors will find that there are many similarities between painting projects and concrete enhancement projects. For example, in both cases, all the necessary tools and materials should be on site before commencing. Additionally, a steady hand and attention to detail are just as important when working with concrete as with traditional painted surfaces.

Perhaps the most crucial similarity is the need for comprehensive surface preparation prior to applying product. Just as you wouldn’t apply paint directly over walls or trim surfaces without removing dirt and flaking paint, decorative concrete specialists ensure that their concrete surface is free of loose material and contaminants before applying stains or coatings.

Of course, there are also significant differences between concrete work and traditional painting projects that must be addressed. In the area of adequate surface preparation, for instance, concrete requires more work and involves different techniques. When painting, preparation includes power washing, scraping, sanding and priming. With concrete, preparation includes examining the surface to determine if there are any clear sealers or waterproof coatings that must be removed, and conducting tests to measure moisture and vapor transmission, which can substantially affect how a stain will react with the surface. Also, any surface defects must be removed or repaired, if they cannot integrate with your layout and design objectives.

Painting contractors who are interested in pursuing work in the decorative concrete arena will need to make a modest investment in equipment. Depending on how much business is anticipated, equipment such as a floor scrubber, shotblaster, angle or disc grinders can be rented or purchased. A small investment in time and money should be allotted in order to receive training in the various techniques necessary for professional stain application. Many industry manufacturers offer one-day, two-day, or three-day seminars with hands-on opportunities to learn everything you need to know.

For a more detailed explanation of the preparation required prior to staining concrete, please refer to the article entitled “Preparing Concrete” in PaintPRO’s February 2001 issue.

Stains are not paints
Working with chemically reactive stains is very different from working with paints. “Stains are not coatings,” says Robert Harris of L.M. Scofield Co., a leading supplier of chemically reactive stains. “They’re designed to color a surface by penetrating it without hiding or covering it. The stains are transparent, or semi-transparent, which means you’ll sometimes see imperfections in the concrete substrate show through. You need to honor those imperfections and incorporate them into your design.”

Furthermore, stains can look very different from one concrete surface to the next, because the age and condition of the floor can have an impact on how the stain is received. “Each floor is going to be unique and different,” says Darke. “You can try to duplicate patterns or approximate colors, but no two floors are alike. They’re like unique palettes on which you can create personalized pieces of art.”

Lee Levig of Concrete Works, a California-based contractor, points out, “This is not a coating, it’s a chemical reaction. If the slab has more lime in it, it’s going to react differently and give you a lighter shade. If there are petroleum products in the slab not visible to the eye, they will also react and result in a darker color. That’s why these stains can be tricky to work with. You have to be upfront with your customers and explain that there’s a certain amount of unpredictability involved in using these products.”

For newly poured concrete floors, color can be added at the ready-mix plant or in dry-shake formulation during the curing process. Painting contractors, however, should concern themselves primarily with existing slabs and how to color or stain them.

The most basic concrete enhancement is to stain a floor one color, which is certainly more visually appealing than plain gray, but there are literally hundreds, perhaps thousands, of examples across the nation of far more elaborate and compelling designs involving multiple colors, intricate geometric shapes, and even corporate logos. These are achieved by creating a design on paper, measuring it out on the slab, marking it with architectural chalk, and carefully sawcutting the design into the concrete.

Sawcutting creates partitions or patterns with the colors, and can prevent colors from bleeding into one another. In addition, the sawcuts can be used as grout lines for additional accenting.

Sawcutting equipment comes in a variety of sizes and capabilities, from hand-held angle grinders to large walk-behind tools. For the painting contractor who can’t invest much in new equipment, Engrave-A-Crete, Inc. an industry leader in concrete cutting equipment, offers a SawKart, a precision-milled vehicle that holds certain brands of circular saws. “It’s our basic beginner tool,” says CEO Darrel Adamson. “It also has a circular cutting attachment that allows for cutting arcs and circles. We’re about to introduce a Super SawKart that has a vacuum port on the back. We also have many other professional cutting tools for the more advanced contractor.”

The creation of dust is a given when using this equipment, which means vacuum attachments, or a co-worker following behind with a shop vac, are necessary. The use of appropriate safety equipment is critical as well, including work shoes, gloves, safety glasses and ventilation masks.

Creating faux effects
As the market continues to grow, practitioners are trying more and more new materials and tactics to achieve unique designs in concrete. One method gaining in popularity is the “resist” technique, which involves the selective use of a sealer to prevent the stain from penetrating certain areas of your surface. For instance, when the design calls for two colors, one light and one dark, the lighter stain is applied first over the entire area. Then an acrylic sealer is applied to only those areas you want to remain light. After the sealer has dried, the darker color is applied over the entire area, but it can be wiped off the areas where the sealer was applied. The result can be a very dramatic, clearly defined contrast of colors, not unlike a tile floor or carpeting, but with far more durability.

Sprinkling various fine materials onto freshly applied stains has been shown to produce interesting effects. For instance, the sporadic yet imaginative use of fertilizer, Miracle-Gro, metal shavings, sawdust, even kitty litter as accents on alternating squares of a checkerboard design can create an exciting, attention-getting look. Some designers have called for the use of wrinkled cellophane or plastic sheets on wet stain to achieve a marbleized, textured appearance. Still others have produced the look of vines and leaves by carefully applying stain into a curvy sawcut and using a compressed air hose to blow the stain out in fan-like designs.

Painting contractors who are initially unsure of their abilities and are therefore hesitant to use something as unpredictable as acid stain might want to consider one of the alternative products, such as QC Construction Products’ Cemtint. “It’s a deep penetrating pigmented sealer,’ says Darke. “The penetrating sealer carries the pigment down into the concrete pores. Because the porosity of a slab can vary, it ends up giving a variegated, marbled, patina look, very similar to the look of chemically reactive stain, but it’s far more predictable to work with.”

Acid stains are the future
Still, acid stain appears to be the material of choice and the direction in which the industry is headed, many observers say. “Right now, acid stains are being specified in most of my projects,” says Levig. I’m doing mostly residential interiors, and 90 percent of my customers are architects. They come to me in the planning stages and say, ‘What do you think? Can we achieve this with stain?’ It’s great to be part of the design stage. We just finished a family room — actually, kind of a trophy room — that uses gold and amber with black splashed on top. It looks like a leopard skin floor.”

Commercial applications of concrete stains have been around for 15-20 years or more — theme parks, Las Vegas casinos, resort hotels and corporate headquarters lobbies, to name just a few. More recently, restaurants, coffee bars and other retail locations have seen the wisdom of combining the elaborate and unique designs typically found in carpets or tile with the durability of concrete. The newest frontier is the high-end residential market, where stained concrete floors are showing up not just in basements and laundry rooms but also foyers, living rooms, or even entire houses, including kitchen countertops.

“Concrete is a dynamic and versatile material, and the color opportunities and options are endless,” says Harris. “When you’re using concrete, your only limitation is your imagination.”

The writing is on the wall… or the floor, as the case may be. Stained concrete is an opportunity waiting to be capitalized on by the savvy painting contractor who wishes to expand his or her business, profits, and customer base.