Article No: 69
Concrete may be as old as the hills, but now it's putting on a pretty face
By: Adam Ford
The Romans referred to concrete as liquid stone. It was cement that allowed the most famous monuments and constructions of the ancient world to be completed, marking the most significant change in building design the world has ever seen. With the use of cement, architects were freed from the constraints of the past, from the limitations of quarried stone and its limited strength to size, from wood and the diminutive stature its buildings always possessed. Cement enabled the ancient architects to design with their imaginations, instead of their restrictions.
As anyone in the construction business surely knows, cement has not yet stopped evolving. The science of cement manufacture and production is continuing to make great strides, enabling new and imaginative processes to be invented.
Decorative concrete is on the forefront of this growth. With such techniques as stamping, staining and integral color, homeowners and designers can create an unlimited array of outdoor and textured surfaces and flooring options. These all enable the designers to escape the one flaw seen with concrete: as a finish material, its starkness can be downright plain. For instance, the durability of concrete makes it perfect for a driveway, patio, sidewalk or floor, so a means to "dress up" or disguise concrete without sacrificing any of the versatility is the goal of many of these manufacturers.
One of the first ways to transform concrete is through integral coloring. This is where pigment, usually iron oxides, is added directly to the mixing truck. The mix is then poured normally, producing a colored slab of concrete that will not fade because the color is literally a part of the mix. These colors can range from subtle pinks and browns to deep blues and greens.
This is usually done by adding a precisely measured bag of pigment to the concrete, taking into consideration the amount of cement, total yardage of the truck and individual properties of the chosen pigment. The drawback of this dry add-mix is apparent when trying to attain the same color for different amounts of cement. Because the pigment attaches to the cement, the same pigment added to a five-sack mix will be much darker than that of an eight-sack mix.
Solomon Colors (www.solomoncolors.com), a provider of integral coloring, has developed a method to ease this measuring process while obtaining a palette of more than 2,000 colors, according to spokesman Bill Duvet.
"By using four distinct liquid pigments, added together in the correct ratio (similar to a four-color printing process), a huge variety of color is available," Duvet said. Solomon reduces the rather complicated mathematics of the mixing by using a mechanical pigment mixer coupled with a computer program. All of the characteristics of the concrete are plugged in, and the computer calculates, measures and tests the resulting pigment for accuracy.
All of the characteristics of the concrete are plugged in, and the computer calculates, measures and tests the resulting pigment for accuracy. A pump then adds the color directly to the concrete. This has proved invaluable to concrete manufacturers.
Integral color has many uses for the concrete industry. Concrete roof tiles, garden accessories and pre-fab concrete pipe are all starting to use integral coloring.
Increte Systems (www.increte.com) has developed a cast-in-place concrete wall that, using integral color and a patterned form, can resemble a stone or masonry wall of any type. Because of the density of the concrete, these walls have become especially popular for sound deadening.
Other methods of coloring concrete are more appropriate for different applications. For instance, many companies make both dry and liquid color hardeners that can be scattered or sprayed on top of newly poured concrete, and once worked into the surface, strengthen the concrete while allowing the use of any color.
One of the most popular methods for decorating concrete today is with the use of acid staining. Many residential and commercial customers are using this method for obtaining a durable, beautiful and relatively inexpensive way to decorate their floors.
While this concept is not new (Frank Lloyd Wright used some acid stains), innovative ideas are expanding the range of the acid stained look. Multiple stains may be used to enhance the depth of the color, grout lines may be cut into the concrete to resemble tile, or highly detailed murals or rosettes may be stained for any surface outside or inside the home.
Charles Leland, a spokesman for of SureCrete Design Products (www.surecretedesign.com), explained the process. Essentially, an acid mixed with a metal-ion reactant (the color depends on the reactant) is applied to the concrete, and creates a color when the alkalines in the concrete react with the acid. Leland said his reaction phase takes about a day, and the concrete requires only a sealant and wax to create a finished surface.
The texture and shape of the concrete surface is being addressed with some of the most exciting developments in concrete design. Stamping, coupled with the new area of thinset overlays, is taking concrete flooring into a new realm of possibility.
Said Marshall Hoskins of Specialty Concrete Products (www.scpusa.com): "Stamping is definitely our flagship product right now. It really seems to be taking off…." Stamping might seem quite simple. A reverse pattern or mat is pressed into wet concrete to create a raised impression of the stamp. The concrete would then look like stone, brick, tile, wood, limestone, flagstone, or just about anything else.
Stampmaster (www.stampmaster.net) and Stampcrete (www.stampcrete.com) are two such companies that manufacture these stamp mats. Many homeowners are delighted by this option, as opposed to costlier stone and brick.
This appeal of stamping can be amplified with the use of possibly the most innovative of the budding concrete technologies overlays. Overlays are thin cementitious materials that are applied over existing concrete to create a new surface. These overlays, while behaving similarly to concrete, are technically a different material often containing polymer modifiers that enhance the malleability, resistance and strength of normal concrete.
These characteristics enable overlays to be applied at thicknesses from 1/16 of an inch, which makes them especially attractive to customers wanting to refinish an already existing concrete slab. "Overlays have been around since the early 1990s, but the market is just getting started," Leland said. He said he bases this opinion on ever improving chemistry and science used in the production of these overlays.
Elite Crete (www.elitecrete.com) is producing an innovative overlay. Spokesman Greg Chapman explains, "Our new overlay bonds chemically with the concrete instead of mechanically sticking like paint." This prevents the thin overlay from flaking off, and acts as a seal against moisture as well.
One of the most common uses for overlays is around a pool or deck. Texture can be added to the mix, which creates a non-skid flooring that is perfect for wet feet.
Specialty Concrete Products' Hoskins said overlays also have a use above the ground in concrete countertops. Specialty Concrete Products is producing countertops with these coatings, which makes a countertop that is as durable as granite. "These can be pre-cast or poured in place," Hoskins explained. Acid stains and integral color can be used on these as well. These are just a few examples of this technology.
Coupled with staining and stamping, a number of options are available for designing decorative concrete. Indeed, all of the processes described here can be mixed and experimented with, limiting designers to only what they can imagine. There are a few places for the curious designer to experiment with these options.
Master Builders (www.masterbuilders.com) may be widely known for manufacturing concrete materials, but they have recently helped produce an interactive online test grounds (www.concretelifestyles.com). The site allows the user to swap patterns and colors to see different styles.
The most impressive thing in outdoor and indoor concrete today may be what has yet to be constructed.