Specifying Concrete - October 2010

By Jessica Chevalier

Travel Solutions is a woman-owned travel agency that organizes business travel events for establishments such as The Limited and Ohio State University. Located just outside Columbus in New Albany, Ohio, Travel Solutions is housed on the first floor of the new Water’s Edge development, a 265,000 square foot project situated in a green landscape that includes a reflecting pond and a fountain. For its offices, Travel Solutions was seeking flooring that reflected an elegant, contemporary and European-inspired aesthetic, as well as one that conveyed the company’s concern for the environment. Stained and polished concrete met these requirements, while also offering durability and ease of maintenance for the growing business.

As Water’s Edge is a new development, Moody Nolan, the architect of record and design firm for the project, was able to be involved in the early stages of the building process, including the specification process for the concrete slab. This involvement was crucial to attaining the granite-like look that Moody Nolan designer Eileen Goodman hoped to achieve for Travel Solutions.

Legacy Commercial Flooring, the project’s flooring contractor and a Starnet Member, did a number of sample pours for Goodman to see what size aggregate best fit her vision for the floor. Goodman chose a mid-sized aggregate made of creek gravel. The gravel includes brown, black, grey and creamy beige tones. The concrete itself is a color that Goodman calls chinchilla, a brownish taupe. This shade is the natural color of the concrete and lends a warm aura to the office. The Travel Solutions floor features a blue, black and red design stained over 20% of the natural concrete. Saw cuts outline the pattern, creating greater definition between the natural and stained segments.

Though stained and polished concrete experienced a surge of popularity a few years ago, some believe its popularity is waning, while others, such as Goodman, feel that the gospel of polished concrete is just now making its way through the ranks of designers outside of major metropolitan markets. In large part, the growth and success of stained and polished concrete as a floorcovering depends on the education of all involved parties—designers, clients, facility managers and maintenance staff. What must be understood about concrete flooring, first and foremost, is that it’s a natural and imperfect material. Installing a concrete floor is not like installing VCT, carpet or ceramic tile. The finished look is not guaranteed.

What’s more, the process of installing, staining and polishing concrete is a lengthy one. To start, a newly poured concrete slab must cure for at least 28 days. If the slab is existing, the contractor must conduct tests to determine the floor flatness and levelness numbers. The surface must be within a particular range in order for the polishers to achieve a uniform level of aggregate exposure.

Though the Travel Solutions project used a new slab, there is one significant benefit to using a previously poured concrete slab. A previously poured slab has had time to settle, so the majority of cracking has likely occurred. However, since the designer and contractor have no ability to control the aggregate used in an existing slab, the true nature of the floor is not revealed until it is polished—the sort of uncertainty that most designers and clients could live without.

Once the slab has been cured, the contractors use a series of diamond pads to polish the floor to the level of aggregate exposure that the designer has specified, with looks ranging from “salt and pepper,” which features small-sized aggregate exposure, to what is called “poor man’s terrazzo,” a chunkier look in which more aggregate is exposed. This process begins with a 50 diamond polishing level. At a 200 diamond level, the floor is at its most porous and ready for design and stain.

If designs are utilized, as they were in the Travel Solutions project, they are outlined by the contractor using flexible design rods, or they may be measured and taped out. The contractor then cuts the designs using a hand saw. Next, he tapes off the sections to be stained and stains them appropriately. Legacy uses penetrating stains that permeate the concrete about the thickness of a business card; this new generation of penetrating stains does not “walk off” as the previous generation of stains was known to do. A densifier is then applied to harden the floor and cause the pigments to crystallize. Finally, the cuts are filled with polyurea or another joint filler, and the floor is polished to the desired sheen level. A 400 diamond polish level achieves a matte look; a 3000 diamond level is high gloss.

Key to this process, for Travel Solutions, was sampling. Legacy not only created sample pours to determine what aggregate level Goodman preferred, but also used a portion of concrete—later covered with carpet—as a sample palette. Here, Legacy applied a number of different stains so that Goodman could choose the tones that best fit her vision as well as see how the aggregate expressed below those stains. Legacy also polished the mock-up floor to different sheen levels. For the Travel Solutions project, Goodman had anticipated wanting a matte finish, but, at sampling, realized that a mid-level sheen helped the aggregate “pop” and brought life to the floor.

Goodman has used stained and polished concrete flooring on a number of educational and commercial projects previously. She appreciates the material’s green attributes and also its clean, monolithic look, which is often fitting for the types of designs that she creates. However, Travel Solutions was the first corporate project to incorporate the flooring type. Goodman believes that this is because corporate environs generally call for a very controlled look. Travel Solutions, which had had a section of concrete flooring in the lobby of their previous office, was comfortable with the natural beauty and imperfections of concrete. However, clients seeking a pristine floor should be steered towards predictable installations like tile and VCT. Goodman suggests taking clients who are interested in the flooring to see already-installed concrete floors, since, very often, negative experiences with concrete are a result of unrealistic expectations.

Visiting finished floors is not only a way to educate clients but also a means through which a designer can vet contractors. Goodman notes that she has concrete contractors with which she feels comfortable. If those contractors were unavailable, Goodman admits that she would be less likely to choose concrete flooring, since the relationship between the contractor and the designer is integral to achieving a successful result. However, visiting job sites—independent of the contractor who completed the work—is a good means of gathering feedback. Facility managers and owners will be much more comfortable discussing their experience in the absence of the contractor. Goodman recommends visiting floors that have been down for a year or more, since flaking and stain loss would likely have begun showing by that time.

Goodman also notes that it’s important to set expectations during the bidding process. Outlining the requirements for sampling as well as time expectations will help the process run more smoothly. Stained and polished concrete is a completely unregulated industry; therefore, designers must be wary of bad and inexperienced contractors, who often come in with low bids. Since the flooring will likely be down for decades, it is all the more imperative that it be installed correctly to begin with.

Lastly, Goodman advises that all involved parties should be made aware of the time commitment needed to complete a concrete floor. Since the Travel Solutions floor took longer to finish than the developer had anticipated, the company was forced to move into the location before the floor had had time to leach. Therefore, though the maintenance staff mopped the floor each evening, Travel Solutions employees would be greeted with a scaly appearance at 9:00 a.m. Though leaching is a natural process, not a problem or health hazard, it is simply an inconvenience to tenants in the space. Optimally, the time line should include a span for the floor to leach before the tenants move in, and all involved parties should be made fully aware of the expected time needed for completion.

With recent advancements in stains and polishing, concrete can offer a clean, contemporary aesthetic or colorful, fun installation. In any case, the resulting surface will likely have a few hairline fractures, perhaps a crack. For Goodman and Travel Solutions, however, concrete’s ability to provide its desired aesthetic in a green package negated the material’s potential imperfections.

CONCRETE IN RETAIL

Concrete flooring is a common choice for many large retailers, including Walmart, for a number of reasons. Stained and polished concrete offers a minimalistic look, serving as a good background on which to highlight products. Also, with a myriad of stains and cutting options available, it is easy to coordinate concrete flooring to a decor package.

Stained and polished concrete is a sound environmental choice for retailers as well, due to its long lifecycle. In addition, concrete is a green material because it generally exists--or is needed--as a subfloor material anyhow. In regard to LEED, concrete flooring can help gain points in a number of categories, including sustainable sites and materials. In addition, concrete has a better coefficient of friction rating when wet than dry, so in an environment like a grocery store where spills are common, it offers an added safety benefit.

However, as an impermeable, long lifecycle material, concrete flooring poses some challenges for retail businesses that alter their layouts frequently. Often remodeling of these locations means moving large pieces of equipment that have been secured to the floor. When this equipment is relocated, the vacated location will likely need patching, which creates a visible variation in the floor. In addition, unlike with carpet, ceramic tile or VCT, a damaged portion of concrete flooring can't be pulled up and replaced. It too has to be patched. For a business in which the floor is likely to endure frequent damage from dropped skids or relocation activities, numerous patches may detract from the finished look of the location.

At $3 to $8 a square foot, concrete has a hefty up front price tag as well, though its maintenance costs are relatively low compared to other flooring choices. Make no mistake, however, concrete is not a "no maintenance" product as many believe--a misconception that has the potential to frustrate clients. Stained and polished concrete needs mopping or auto scrubbing regularly, an occasional burnishing, and annual or bi-annual sealant reapplication to maintain its top quality. Some products such as Prosoco's LS Klean cut down on the need for sealant reapplication. The product actually contains a portion of the company's sealant, so mopping serves a dual purpose.

Because polished concrete is a relatively new flooring material and innovations to the stains and polishing techniques are still evolving, some earlier concrete installations have begun to ugly out. To complicate this, a new floorcovering product can't simply be installed atop the highly polished concrete surface. Instead, the finish has to be blasted off--a costly and inconvenient endeavor--before a new material can be applied. Some manufacturers are currently working to create an adhesive that will make it possible to adhere new flooring directly atop polished concrete, but, as of yet, nothing has hit market shelves.

In many ways, concrete is fighting a tug of war for its position as a floorcovering in retail. Its long life and minimal maintenance offer a decent sustainable story for retailers and other businesses hoping to gain green points in the eyes of customers or for LEED. However, its inability to accept change--without visible scarring--makes it a rough sell for retailers whose success often depends on conveying a fresh image and a pristine atmosphere. Perhaps the best insurance for a company considering concrete is that, with a little work, will serve as a good subfloor for any material chosen to replace it.