Stamped concrete is just one of the many treatments that we use that fall under the category of “decorative concrete”. Simply described, it’s the process of coloring and imprinting concrete to create the appearance of natural paving materials like cobblestone, brick, slate, or any material that you might commonly see used for paving. Although many people have never even heard of it, and those that have think it’s a pretty neat new concept, the process has been around for more than 50 years, though the methods of stamping concrete have improved greatly since then.
Stamped Concrete is the process of coloring and imprinting concrete to create the appearance of natural paving materials like cobblestone, brick, slate, or any material that you might commonly see used for paving
Is stamped concrete better than pavers?
This answer to this question is not straightforward, and can be very situational. Are you hoping to resolve drainage issues? Does your situation require pervious paving materials? Is it easily accessible? Is it a very large area or quite small? Are you more interested in a contoured layout or does something very linear appeal to you? These questions can help determine which might be best for your situation, but they can greatly impact function, durability, budget and design.
I would be happy to discuss your particular situation, but whatever the case, you would want to hire a quality contractor to do your work. With stamped concrete, an inferior job is usually evident right off the bat. With brick pavers, the easiest shortcuts (which we see pretty consistently) that can cause problems down the road, may not reveal themselves for a couple of years – beyond a standard warranty period.
How is stamped concrete installed?
Over the years we’ve developed a variety of processes and tricks that give us better results, but trying to explain that to a layperson can get pretty confusing, so I’d like to describe a very simple application with no bells and whistles just to give you a better sense of what it is.
Let’s start with a simple stamped concrete pad that we want to look like gray cobblestone.
Preparing for stamped concrete installation
The prep work for a stamped concrete pad is no different than that for installing regular concrete. We remove whatever materials are in the way and the area is prepared with a compacted stone base, it’s formed up, reinforcing installed, and then it’s ready for concrete. From this point on, things take a slightly different tack.
Initial colored concrete pour
The concrete is ordered and may already have a color added to the mix, which is called an integral color, or it might not, in which case an alternate color process might be used. For this simple case, the gray cobblestone look, we would have it delivered with a medium gray integral color. The colored concrete is placed and initially screeded and floated to provide a uniformly finished surface, and then left for a short amount of time to start the hardening process.
Applying the tinted release powder
When the concrete has gotten firm enough to support the workers and tools that make the cobblestone impression, we will apply a tinted release powder (or clear liquid) that does a couple of things. First, it creates a barrier between the imprinting tools and the concrete that prevents the tools from sticking to the soft concrete. Second, there is usually a tint incorporated into this powder that ends up getting worked into the stamped impressions – meaning the joints and character marks – made by the tool. For this simple case we will use a gray that is slightly darker than the color in the concrete mix. With this thin layer of powder in place we are ready to start the imprinting process.
There is usually a tint incorporated into a powder that ends up getting worked into the stamped impressions – meaning the joints and character marks – made by the stamp tool
Stamping the concrete
Now, the tools used to make the impressions are referred to as stamps. They are made of semi-rigid rubber and are usually about 3’ square and about an inch think. On the top are handles used to pick up and place the stamps and the bottom of the tool has the reverse form of the impression you are making. A set of these stamps may have 10 or more pieces that fit tightly together.
The tools used to make the impressions are referred to as stamps.
With the release powder down, we are ready to place these stamps. We take great care in placing the first couple of tools as these will control the alignment of the stones for the entire stamped area. After we get a number of stamps in place, we will work to impress them into the concrete surface. We want them to go in just enough to fully impress the pattern, no more, no less. Early on this may just require stepping evenly on them, and as the concrete gets tighter, it will involve using a hand tamper to impress them with a little more force.
After the stamps that have been set in place have been impressed, we will pick up the first ones that we originally placed and leap frog them from the beginning of the stamped area to the leading edge of the direction we are headed. Those stamps are impressed and the leap frog action continues until we have stamped the entire concrete pad. We will then leave the pad to tighten up overnight.
Cutting the control joints
Within the next 24 hours or so we will cut the appropriate control joints that help control any concrete cracking and start the clean up process. This involves pressure washing and scrubbing with a buffer. In this process, the critical thing is to remove the primary component of the release agent that was applied before stamping. What will be left behind in the joints and character marks of the cobblestone will be the tint color that was a part of the release. This color will have been permanently imbedded in the concrete.
Applying the sealer
Once the surface has been fully cleaned and is totally dry, we apply the seal coats. For most applications this will be an acrylic sealer with an added abrasive to improve skid resistance.
Then it is left to dry. For pedestrian areas, we usually like it to dry overnight before the customer walks on it, but it’s really dry enough to walk on within an hour. For driveways or other vehicular areas, there are other considerations with loading for several days, but one can still walk on it shortly after sealing.
Want to learn more?
So that’s about as simple as it gets. As I noted, there are a ton of other methods or tricks that we have figured out over the 20+ years that we’ve been doing this that we use to improve the end product, and I’d be happy to discuss these with you in more depth if you’re interested. With this blog post, though, I hope I’ve given you a better understanding of the process of concrete stamping and answered your question – what is stamped concrete.