DIY Sunken Concrete Tiles

Clean the concrete tiles with a garden hose equipped with a spray attachment. Spray the water on the surface of the concrete and between the tiles, washing away any debris, such as dirt or leaves, and leaving behind a clean surface.

Measure the dimensions of the damaged concrete with a measuring tape. Purchase lumber the same height as the surrounding tiles and long enough to span the damaged area. Lay the boards around the sunken concrete tile, making a rectangular frame (assuming the sunken concrete tile is rectangular). Nail the boards together with nails from a nail gun.

Pour concrete mix into a plastic bucket and add half as much water as the manufacturer recommends. Mix well. Then add the other half of the recommended remaining water slowly, so that you add the total amount recommended by the manufacturer. Stir the mix briskly, getting the powder off the bottom. When you have the proper ratio of water to concrete mix, it should have a consistency between those of prepared oatmeal and peanut butter.

Apply the concrete mixture to the top of the sunken concrete with a trowel, but don't fill the mold to the top. Put in enough concrete to fill the space about halfway. The concrete will slowly settle over the surface of the broken concrete and fill any gaps or cracks underneath. Leave the mixture in place for 24 hours. As the concrete dries, it slowly drips into any gaps, which leaves behind valleys and dips on the top of the new concrete.

Mix a second batch of concrete and pour it over the surface. The first pour filled the gaps, while the second layer will leave behind a smooth surface. Spread the mixture with a flat trowel. Move the flat trowel back and forth across the concrete until it is smooth and even. Check the surface with a level and smooth the concrete until it is even.

Remove the nails from the frame with a hammer, once the concrete cures and hardens. Depending on the manufacturer, the process should take two to three days. If you use lumber the same height as the undamaged tiles, the new concrete should be the same height as the surrounding tiles. Repeat the steps for any additional sunken tiles.