How to Patch Concrete & Flagstone Steps
- 1). Wear protective clothing, goggles and a paper mask or respirator over your nose and mouth.
- 2). Remove any rough, jagged edges from around damaged areas or large broken pieces of concrete using a small sledgehammer and a chisel.
- 3). Squeeze siliconized latex caulk into any smaller cracks to fill them completely. Use your gloved fingertip or the edge of a metal trowel to smooth the surface of each fill.
- 4). Use a trowel to apply a thin layer of concrete patch onto the surface of wider cracks and holes. Make this layer approximately 3/8 inch thick. Wait 30 minutes to an hour until this layer is softly set. Trowel on a second, thicker layer of concrete patch. Build up each of the damaged areas with the patch product so that they are even with the undamaged surface of the step. Smooth the surfaces of the patches with the flat side of the metal trowel or a rubber float.
- 5). Fill very deep holes or gaping areas with new concrete. Build small frames from scrap lumber and duplex nails that fit around each damaged area. Lay them into place and put rocks or other weights around the top edges to weigh them down.
- 6). Mix together in a bucket a small package of concrete mix and the amount of water suggested in the directions for your particular product (this will vary by brand). Stir the mixture well with a paint stick or small shovel.
- 7). Pour the prepared concrete into each of the frames and use a handheld spade to smooth the surface and gently tamp the concrete into place.
- 8). Cover the frames and other patched areas with plastic tarps and leave them in place for a week. Once a day, pull the tarps back and use a fine misting spray bottle to gently spray each area of curing concrete with water. Recover the areas with the tarps.
- 9). Remove all of the tarps, frame and other items after seven days.
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