Stamped Concrete 101
This sections main focus is on the basics of stamped concrete. However, we can’t forget that although stamped concrete looks very different from the traditional “gray” concrete that we see throughout our daily lives, in the beginning stages it is installed in the same manner using the same methods that have been used for decades. To ensure beauty and longevity as an end result, proper concrete placement techniques must be adhered to in the beginning stages. When choosing an installer be sure and ask about his experience and knowledge of concrete and ask to see examples of projects in your area.
When choosing Stamped Concrete, you will be asked to make many different kinds of choices. Below is some general information to help guide you through the techniques, processes, terminology and maintenance associated with stamped concrete. We believe an informed customer is a happier customer.
Coloring the Concrete – There are two methods of coloring concrete: integral color and color hardener.
Integral color – This is the process of adding the desired color directly into the concrete truck during the mixing process. This leaves the finished product the desired color throughout the thickness of the concrete.
Color hardener – also known as “throw on” color is the process of pouring the concrete in its natural gray color. While the concrete is still wet, the desired color is broadcast or thrown across the surface and worked in with trowels. This leaves the finished product with a thin layer of high density color.
We primarily use integral colors, unless jobsite specifications require the use of color hardener. A color chart will be provided and once a color is chosen, it will set the overall color tone of the work being performed.
Antique Release Agent – This is also known as the “highlighting” color. An additional color chart will be provided and a choice is made on a color to “highlight” or accent the concrete color that has already been chosen. This highlight color is broadcast across the surface just before the stamping occurs and creates a two-tone effect to the overall job. The antique release agent also serves another vital role acting as a non-sticking agent between the concrete and the stamping tools.
There are two mainstream ways of applying antique release agent:
Broadcasting powder – This is the technique of “throwing” on dry powdered antique release agent over the “wet” concrete, just before stamping. This powder is then washed away at a later time.
Spraying on liquid – This is the technique of spraying liquid antique release agent over the “wet” concrete, just before stamping.
Both ways of applying the antique release agent are viable, however, due to clean up issues(especially around pools) and disturbance to adjacent properties, we primarily use the spray on liquid method of applying antique release agent.
Patterns – When choosing a pattern there is no right or wrong choice, it comes down to preference. That being said, some patterns will suit certain projects better than others. For example, in a long winding walkway, you may not want to use European fan. Be sure to look at our photo gallery and patterns page to get a good idea of what each pattern looks like up close as well as the overall tone it sets. Also ask your salesman for advice and if your still undecided ask to see some examples. Please inquire about custom stamps and logos.
Sealer – Sealing stamped concrete is an important and often overlooked step in a stamped concrete project. There are many different types of sealers for many different applications. For most projects, an EPA approved, solvent based acrylic sealer that is UV tolerant will be fine. However, not all sealers are equal and cutting corners at this phase can ruin a project. You should always inquire about the type of sealer being used on your project. Make sure the sealer is EPA approved in your State and also write down the brand/type for future reference. In the event a project requires special considerations regarding sealers, please talk to your contractor in advance about these needs.
Non-skid surface – Typically, stamped concrete is made slip resistant during the sealing phase of a particular project. Some installers use non-skid additives that are directly mixed into the sealer, while others broadcast skid resistant materials across the concrete surface just prior to sealing. A reputable stamped concrete installer will never minimize or overlook this simple but very important step.
Expansion Joints – Expansion joints can be constructed from many different materials, such as: wood, Styrofoam, bituminous asphalt strips, and closed cell foam. The role an expansion joint plays is to fully separate fresh concrete from other fresh concrete or from other existing concrete. For example, when pouring a 4” thick stamped concrete patio against an existing concrete foundation, a 4” expansion joint should be used to separate the stamped concrete patio from the concrete foundation. This allows each piece of concrete to expand and contract independently of one another. If expansion is not used in an example such as the one above, chipping and cracking can occur where the two separate pieces of concrete meet together. Expansion joint should always be used.
Control joints – Control joints are very different from expansion joints. There are many different methods and products used to install control joints such as: saw cuts, vinyl pool joints, hand tooled grooves, and many others. Since concrete will crack predictably in many areas, control joints are put into place to “invite” or “control” a crack to the installed control joint. Experience and expertise are needed when installing control joints and many times, they must go in areas where they are not aesthetically pleasing.
Cracking – Cracking is a major issue in stamped concrete and one that must be addressed by your contractor. Generally, all concrete is susceptible to cracking, however, choosing a contractor with extensive knowledge, expertise, and quality workmanship can greatly reduce but not eliminate the chances for cracking. Many factors, that go well beyond the scope of this forum, contribute to concrete cracking. Some of these factors are: excessive amounts of water used in the concrete mix, poor sub-grade compaction or settling of the sub-grade, primary and secondary reinforcement, installation of control joints, and installation of expansion joints. Choosing a qualified stamped concrete contractor with many years of experience is the best way to minimize cracking in your stamped concrete.
Deicers – As a general rule, we suggest avoiding the use of deicers on concrete when possible. They increase the amount of freeze-thaw cycles the concrete must endure and are generally not good for the environment. If deicers are necessary, we recommend using magnesium chloride (best) or potassium chloride in small amounts. They are the least detrimental to concrete, while being easier on the environment. Never use rock salt. If salt intrusion is a concern, specific sealers are available.
Resealing – Stamped concrete is considered a low maintenance product. We recommend resealing every 1 – 3 years, depending on each individual project circumstance. Of course, high traffic areas such as driveways and parking lots will need to be maintained more regularly than a small patio with occasional use. Never apply a sealer that you are not sure of. We have seen many people use inferior products to reseal and have great difficulty rectifying the damage. Our recommendation is to hire the installer to reseal or contact them to purchase a compatible sealer. If this is not possible, contact a reputable installer in your area, most are happy to help.
You are now on your way to making a more informed decision when choosing a Stamped Concrete installer. Thank you and good luck!