How to Jack Up a Sunken Walkway

Cut the concrete walk between the piece of walkway that has sunken and the piece that is still at the correct height. Use a concrete saw with at least a 12-inch diamond blade to make the cut. Cutting between the slabs allows the sunken piece of concrete to move up without hitting any of the slabs next to it.

Drill two holes in the sunken slab of your walkway using a concrete core drill. Drill each hole at either end of the sunken slab. Make sure you drill down to the sand or gravel layer under the walkway. Save the core pieces, as these will be replaced in the holes once the walkway has been raised.

Dig down through the holes just drilled using a rock hammer. Make sure the holes are at a depth of about 1 foot. This deeper hole will allow you to inject concrete grout into the void beneath the walkway.

Pump the concrete grout into the holes. Alternate between each hole by partially filling up the void under the slab then moving on to the next hole. Repeat this process until the slab is back up to the desired height.

Wipe off the excess grout from around each hole with a rag. Fill the hole with a small amount of excess grout. This additional grout will help hold the concrete plug in place.

Insert the concrete core plug into each hole. Use a small amount of regular concrete mix to fill any gap around the plug. Smooth out the excess concrete mix with a hand trowel.