Stenciled Concrete Looks Similar to Stamped Concrete
Like stamping, stenciling is done in fresh, still-workable concrete. However, it differs from stamping in that the pattern is made by disposable paper stencils instead of polyurethane stamp mats. Aside from how they’re installed, the main difference between stamped and stenciled concrete is that stenciled concrete exhibits realistic-looking gray “mortar joints”. These are created by the stencils masking off the plain gray concrete underneath. Rolls of stencil come in a variety of patterns.
Below is a brief overview of the installation steps involved with stenciled concrete.
Before the job begins, a base color, secondary color, and pattern are chosen. The base color for stenciled concrete is provided by dry shake color hardener. Dry shake color hardener is a powdered mixture of pigments, sand, and cement. While the concrete is still in its plastic state, the dry shake hardener is applied to the slab’s surface and worked in. It will ultimately make the top of the concrete harder than normal by densifying the surface.
Laying the stencil
Next, an antiquing or “highlight” color is chosen. The highlight color is provided by antiquing release agent. This is a colored, waterproof powder (or sometimes liquid) that keeps a texture roller or stamping skin from sticking to the concrete while texturing it. To make stenciled concrete more variegated and realistic looking, it is best to choose an antiquing color that contrasts with the base color you chose for the concrete. For example, you could choose a brick pattern where the base color of the “bricks” is red and the antiquing is dark brown.
When the color and pattern choices are finalized, the slab is formed, prepped, and poured in the normal manner. After the surface is screeded (leveled) and bullfloated (smoothed off ), two workers begin placing the stencil by stretching it across the slab. One piece of stencil is laid next to the other until the entire slab is covered (see photo above left). To avoid a double-width joint between pieces of stencil, the outside joint of the piece being placed is overlapped atop the outside joint of the previous piece.
Applying dry-shake color hardener by hand
The stencil is then slightly embedded into the surface with a special roller so that no color can get beneath it. The moisture in the wet concrete helps stick the stencil down. Dry-shake color hardener is then applied to the surface and worked in with a float (see photo on right).
Applying the Antiquing Release Agent
Next, the antiquing release agent is applied and a textured roller or embossing skins can be used to add realistic detail.
Removing the Stencils
When coloring and texturing are complete, the stencils are removed from the slab to reveal the plain gray “mortar joints” beneath.
Sealer darkens the color dramatically
After the concrete has hardened sufficiently, contraction joints are sawed into the slab to control random cracking. Excess antiquing release agent is cleaned off, and the surface is allowed to dry. Clear sealer is then applied to the concrete in order to protect it and enhance its color.
Enjoy Your Stenciled Concrete
After giving the concrete time to cure (your contractor will tell you how long to wait), you can enjoy your new stenciled concrete! For more on concrete stenciling, read the article entitled An Alternative to Stamping, or view a 3-minute video of the stenciled concrete process by clicking here.