surrounding steps and riser stones, and we did NOT want to rebuild the entire staircase; we wanted to repair it. So, we tried our luck in a near- by creek and extracted an actual chunk of limestone from the mud bed. The rock had a fairly flat face and roughly measured the right size and shape (and even color) we needed. This is the type of out-of-the-box solution you won’t find in a home-repair man- ual, so we had to get creative with how to fasten the stone into to the steps. A quick trip the local home center produced the strongest adhesive we could find at the time: anchoring epoxy. This is a commercial-grade, fast-setting, two-part structural epoxy that’s used for setting anchor bolts, threaded rods, railings and rebar dowels into concrete and mason- ry. Seemed like tough stuff, so we applied it liberally to the back and sides of the stone, but did not completely fill the edges joints to leave room for joint mortar. After the epoxy dried, we caulked the joints around the stone with repair mortar to match the surrounding installation. The limestone patch ended up blend- ing well with the flagstone, so the repair was a success. But that was only the first phase of our project. PHASE 2: RECOATING THE FAUX STONE Unless we fortified and resealed the other treads, we would soon be repeating the replacement procedure on the rest of the steps. To avoid this, the steps need to be repaired with a hard, durable cement coat- ing that would bind with the exist- ing concrete. The product also needed to be tintable, and we’d need to color the product in small batches to vary the tones and blend with the surrounding mixed-color flagstone. After a little research we came up with an experimental recipe. The base was quick-setting cement, which comes in a bag that you mix with water. The cement was dyed with Quikrete Liquid Cement Color, which was added to the cement mix—and “a little dab will do ya” because
this stuff goes a long way. We chose two colors, Buff and Terra Cotta, which we combined in varying amounts to closely match the surrounding color scheme. When working with pigmented concrete, keep in mind that the
color will lighten once the con- crete dries. Our “secret ingredient” was an acrylic fortifier. The Concrete Bonding Adhesive & Acrylic Fortifier from Sika Pro Select is ideal for bonding new concrete to old. It’s an important additive to enhance the bond on applica- tions less than an inch thick, like this project. We mixed it into the cement as a supplement to the water (following the directions on the package). Use only enough water to get the cement to the proper con- sistency, which should be some- thing close to smooth peanut butter. To mix the product you’ll need a bucket and powered drill equipped with a mortar paddle. Mix up only enough cement to use in about ten minutes, other- wise it will start to dry out and set up.
Prior to applying the repair cement, the old concrete surface should be cleaned of all foreign matter and loose materials. The bond will always be strongest if all smooth surfaces are rough- ened or etched, so we scrubbed the steps clean with a wire brush attachment in a power dill. Any dust must also be washed from the surface.