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How to get stamped concrete over existing concrete

6/15/2020



People frequently ask how they can get stamped concrete over existing concrete. Tearing out and replacing concrete is costly and invasive. When it's time to upgrade, that makes it a natural question to ask. Fortunately, it is possible to place stamped concrete over existing concrete. Stamped concrete overlays are durable options for upgrading, repairing, and enhancing existing concrete.

Stampable Overlay
Concrete Stamps by Brickform
Concrete stamping


Stamped Concrete Background


Textured concrete is attractive. It is also more economical and durable than many of its natural material competitors. Stamped colored concrete is a premium flooring and paving option with a wide range of benefits that make it a desirable alternative to pavers, standard concrete, and stone. Stamped concrete is created using specialized texturing tools. While it is still plastic, concrete is imprinted using these tools. This creates permanent patterns and textures in the concrete. Color stamp concrete using any combination of integral colors, color hardeners, and stains.

Tear Out and Replace


Replacing concrete can be traumatic! Demolishing and removing reinforced concrete can take several hours for just a couple hundred square feet. There is also additional labor and cost associated with disposal and demolition equipment rental. All of this adds thousands of dollars and hours of labor before the new slab is even started. On top of the added labor and cost, demolishing existing concrete has the potential to damage surrounding areas. Skid steers and earthmovers will destroy landscaping and grass. Heavy equipment and trucks can crack adjacent concrete. For these reasons, it is often best to avoid tearing out old concrete if possible.

Current Concrete Surface


Before you start considering stamped concrete over existing concrete, the existing concrete must be evaluated. As with new placement, the slab is only as good as the subgrade. In this case the subgrade is the existing concrete slab!

First, carefully inspect the concrete for damage. Any significant structural damage will cause problems later on. Examples of significant damage include large cracks, settling, and massive surface deterioration. Major cracking and shifting will cause the concrete overlay to break and crack, too. Surface deterioration and loose materials on the surface will prevent the overlay from adhering. If the underlying concrete is not structurally sound, it is not worthwhile to overlay it.

The Solution


The best way to get stamped concrete over existing concrete is a stampable overlay. Stampable overlays are a thick overlay capable of accepting texture from stamps. These overlays are much thicker than microtoppings but not as much as a self-leveling overlay. Stampable overlays are made from a special blend on polymers, fine aggregates, and cement. This composition creates a durable and easily workable material well suited for texturing. In many keys aspects, stampable overlays act and perform just like concrete.

Surface Preparation


With any overlay process, surface preparation is the most important aspect. As mentioned above, structurally unsound concrete is not suitable for overlayment. Any loose or weakened material must be removed before the overlay is installed. The surface should also be free of contaminants that would prevent a bond from forming. Reference the technical information sheet for the chosen overlay and surface preparation guidelines from ICRI before you begin. Once the appropriate surface profile is achieved, installation can begin.

Installation


The exact mixing and installation method for a stampable overlay depends on the exact product chosen. For example there are two Brickform Stampable Overlays. OL-60 Stampable Overlay is the gray overlay designed as an add-water product compatible with Color Hardener/ SC-60 Stampable Overlay is a white add-polymer mix that is compatible with Overlay Liquid Color. Once either overlay is mixed, the material is applied using a gauge-rake, squeegee, and/or trowel. After sufficient set time, the overlay is textured like stamped concrete using a texture skin or traditional stamp. When using traditional stamps, be aware of the impression depth. Install the overlay at the correct depth to avoid bottoming out with the stamp.

Colors


Stampable overlays use some of the same methods as stamped concrete coloring. They also use some unique methods. Overlay Liquid Colorants, which are pre-measured integral colors designed for use in overlays, are unique to overlays. Other stampable overlays are colored with Color Hardener applied in much the same way as in traditional stamped concrete. Highlights are made possible with powdered Antique Release or a combination of Liquid Release and Antique-It applied later. Also like cast in place concrete, stampable overlays can be stained using water based stains. This adds depth and uniqueness to designs if you are willing to put in the effort.

Whether you want stamped concrete driveways, patios, sidewalks, or interior stamped concrete, a stampable overlay may be the best choice. When you want to get stamped concrete over existing concrete, a stampable overlay is a durable and versatile choice.