Taking Stamped Concrete Over The Edge

by Jeff Potvin, The Concrete Network

Stairs and cantilevered coping are a common component of a stamped concrete project. A set of stairs can be a simple box or simulated slabs of stone and the edge of a pool can be a white piece of aluminum or layers of brick or slate. One of the first things I learned to form and stamp were intricate stair treads and risers. Through my years of experience and mistakes I learned a few tricks that complete a job with eye catching edge details.

Forming a set of stairs can be a tedious mindless job or the erection of a work of art. A couple of things to keep in mind while forming are clear access to the treads for stamping and ease of stripping. Keeping the bracing to a minimum and cutting the bottom of the riser on a 45 degree angle will give way to easier stamping. When stamping with color hardener it has a tendency of building up in the back corner of the tread, making stripping the cantilever a nightmare. Setting the riser at a ¼" above the finished tread and using the point as a guide will keep the corner clean, making stripping easy. Another little trick that helps leave a nice edge on the cantilevered coping is to vibrate the concrete while placing it in the form. Since tapping the foam form with a hammer is out of the question, use an electric palm sander as an external vibrator.

Finishing the face of a set of stairs or the edge of a pool deck can be a time consuming job but it is well worth it. The first step is too thoroughly clean the surface. I like to use a wire brush since it will remove any loose sand or aggregate. Make sure to remove any residual release agent, it will definitely be a bond breaker. Also, taking a hand grinder to the edger line and continuing the grout lines over the edge will help add to the overall look.

After the surface is good and clean, brush on a good quality bonding agent. Mix a quarter of a pail of color-hardener and water to a pasty like consistency. Allow the color to sit a couple of minutes and re-temper it. Use a small pool trowel to butter a ¼" of material onto the face without over troweling. Make sure to rub the top so that the surface looks continuous. Once the material begins to fatten up, apply the release agent and texture the surface making sure not to use the same area of texture each time. Finally use a roller or brick jointing tool to press the grout lines into the textured area. If you prepare the surface for sealing by acid washing, make sure not to let the acid solution run over the edge without diluting it or scrubbing it with a broom. This will prevent run marks on the face.

If the riser is cantilevered, I usually texture the top area and brush dry release into the wet hardener underneath, which will make that area darker. Once sealed, the stairs have more of a three dimensional appearance.

Jeff Potvin

Jeff Potvin, a Civil Engineer and the owner of Architectural Concrete Consultants, has nearly fifteen years of experience in the architectural concrete industry. His experience includes stamped concrete, overlays, form-liners, acid stains, counter tops and coatings.

He helps contractors get started in the industry with hands on training, promoting, product selection and troubleshooting. Property owners such as theme parks and retail stores consult with him on product sourcing and maintenance issues. Architects and Engineers utilize Jeff's knowledge on the preparation of specifications and on educational presentations. He is a member of ASCE, ACI, ASCC, IAAPA and the DCC.

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