Many homeowners think of concrete as a simple gray material used for sidewalks and boring driveways. But with modern concrete stamping, concrete pros like Sudlow Concrete are creating beautiful designs you would never recognize as concrete.
What Is Stamped Concrete?
Let’s start with concrete itself. Concrete is made of fine and coarse aggregate, basically sand, crushed rock, or gravel, mixed with cement. The mixture forms an especially hard and sturdy material as it dries. Cement was first used on a large scale by the ancient Romans. After the fall of the Roman Empire it largely fell out of use until the technology was rediscovered in the mid-eighteenth century.
Stamped concrete is a much newer concept. While it was used on a very small scale since the 1950s, its widespread use really began in the 1970s. Since then, its popularity has steadily grown. Today, stamped concrete can to look like almost any type of material. It is a popular way to mimic the look of more expensive materials such as stone, slate, and brick. It is also a more durable way to achieve the look of materials such as wood and flagstone.
Stamped concrete is basically regular concrete that has been colored and then shaped by giant stamps to create a texture other than the standard smooth texture of concrete. Stamps come in many different shapes and styles. Today, most concrete stamps are made of polyurethane. In the past they were made of metal, which was heavier and harder to work with and could not create as much detail as modern stamps.
What is Stamped Concrete Used For?
Stamped concrete is an amazing material. It has all of the benefits of regular concrete. It is weather resistance, fire resistant, and incredibly strong. When properly installed, stamped concrete can withstand the weight of a semi trailer truck. It is also relatively low cost. Compared to the many materials stamped concrete can mimic, stamped concrete is a budget friendly material.
Stamped concrete mimics a wide variety of materials. Common uses of stamped concrete are to mimic stone and brick. You have probably walked on many pathways that you assumed were brick that were actually stamped concrete. The finished product is almost indistinguishable from real brick. But the installation is faster and the material is cheaper, making it a very popular alternative. The same is true for cobblestone pathways. The installation of new cobblestone is very rare. Most new “cobblestone” you see today is actually stamped concrete
How Stamped Concrete is Created
Preparing the Concrete
The first step in creating stamped concrete is to lay down the concrete. The concrete has to set to just the right plasticity. Once the concrete has reached the optimum plasticity, a coloring agent can be added. Usually this is a powder called color hardener. Color hardener has the double benefit of coloring the top layer of the concrete (the part that shows) and hardening it to create a more durable surface. The color hardener powder is broadcast over the whole surface of the concrete, usually by hand. Then the whole surface is floated (basically smoothed over) and the process is repeated one more time to ensure full coverage.
The next step is to apply a release agent. A release agent can be applied either as a powder or as a liquid. The release agent, as its name suggests, helps the stamps to be released from the concrete without sticking. This is important, because if the stamps stick to the concrete as they are being lifted they will cause imperfections in the stamp pattern and the surface of the concrete. A powdered release agent is sprinkled in a thin layer over the whole surface of the concrete. A liquid release agent is sprayed on in a thin, uniform layer using a pump-type sprayer.
Another important function of the release agent is to provide a subtle contrast color. The contrast color can come from the powder, which is colored, or from a tint added to the liquid release agent. If the contractor will be using a liquid release agent, it is best to add the tint a day or two ahead of time to let it mix completely with the liquid.
Placing the Stamps
Once the concrete has been prepared, the contractor needs to do one more check to make sure the concrete is at just the right point to take the stamps. If the contractor starts stamping too soon, the concrete won’t be set enough to support the weight of the workers walking on the stamps. The concrete may also not be set enough to hold the texture created by the stamp. On the other hand, if the concrete has set too much, it will take a lot more effort to imprint it with the stamp pattern. The stamp will also not be able to produce the subtle textures you want.
Once the concrete has set to just the right point, the edges need to be pre-textured. This can be done with a texturing skin or a flexible mat. When using inflexible stamps, the stamps will overlap the edge of the concrete and you won’t get the fell texture up to the edge. Pre-texturing the edge makes sure that the edges get the full texture and the full benefit of the release color.
After the edges have been prepared, the first stamp can be laid down. It is best to start from the part of the concrete that was laid down first. This ensures that the first area where the concrete was placed doesn’t set too much before it is stamped. It is very important to get the first row of stamps straight and even, since they will serve as the guide to the rest of the stamps. One easy way to measure a straight line is with strings stretched across the concrete where the top and the bottom of the stamps will be.
Once the stamping has begun, the stamps can be laid down one after the other. Most stamp manufacturers label the stamps with the order in which they should be placed. The contractor should follow this order for the best results.
If the concrete is at the right consistency, the pattern stamp should be imprinted on the concrete simply by laying down the stamps and walking on them. Occasionally this is followed by a little tamping. As each stamp is placed, the stamp before it can be lifted off the concrete and placed ahead of the current stamp, and so on until the whole concrete surface has been stamped.
As the stamps are lifted, there will almost certainly be some detail work that needs to be done by hand. There may be areas where the cement paste has come up between the stamps, blurred areas of the stamp, or areas of grout that are too shallow where the stamp wasn’t applied with enough pressure. All of these can be fixed with hand tools such as a hand chisel, a roller, or texture skin. The texture skin can serve as a sort of eraser, leveling an area to prepare it to be restamped. All of this is best done as the stamps are lifted or at least on the same day before going home.
Finishing the Concrete
Once the concrete has been allowed to set for one, two, or three days (depending on the weather), the remaining release agent can be washed off. At this point, control joints can be cut into the concrete to allow for the expansion and contraction of the concrete with changing temperatures. If the release agent was applied as a powder, the joints can be cut first and the dust from the joint cutting and the release agent can be cleaned all at once. Once the surface is clean, a curing agent is applied.
A few weeks later, when the concrete has completely cured, the contractor can return to apply a finish coat of sealer. By combining both spraying and rolling on the sealer, the contractor can cover the whole surface uniformly without missing any textured areas.
Where To Find the Best Concrete Stamping
Concrete stamping is a specialized technique best applied by an experienced concrete worker. It can create a beautiful effect if done right. If you are considering stamped concrete for your home, TrustDALE has got you covered. Sudlow Concrete has been in the business of concrete installation for almost twenty years and has completed hundreds of projects. They are backed by Dale’s stringent 7-point investigative review process as well as TrustDALE’s make-it-right guarantee. When you work with Sudlow you will get top-notch service and high quality work at an affordable price. Dale trusts Sudlow Concrete, and so can you!