How to Fix a Sunken Walkway

Chisel apart the expansion joints in the walkway that are over the sink. Place the chisel edge along the joints and tap it back and forth along the length of the joint until the joint separates.

Dig out the soil alongside the sunken slab edge at a 45 degree angle. Dig deeply enough to expose the bottom of the sunken edge and set the dug soil aside on a tarp.

Place a landscaping log parallel to the sunken side several inches from the edge. Drive the point of your 5-foot straight pry bar into the ground along the sunken edge. You may have to drive it several times to get it deep enough. Push the handle of the pry bar down over the log, which will act as a fulcrum, and raise the sunken edge. Place bricks every 2 feet or so under the raised edge and let the pry bar rise up, allowing the raised concrete slab to rest on the bricks. Do this with each section that was sunk.

Mix the pea gravel and sand one-part to one-part. Pour the sand-gravel mix into the space under the slab. Each time the mix fills the face of the space, drive it as far back as you can using the end of the 2-inch by 4-inch board, then pour again. Repeat this until the space is full of the sand-gravel mix to what appears level, allowing for the thickness of the slab.

Pry the slab up again with the pry bar and log and remove the bricks, allowing the slab to rest on the sand-gravel bed. Check level with adjacent sections of the walkway. If the edges are barely high, you can jump on the slab to level it. If the edges are high, re-raise the slab and put it back on the bricks. Use your shovel handle to spread the sand-gravel footer until it appears low enough, then lower the slab again. If the slab is low, the re-raise it and add more footer material.

Replace the soil along the edge when the walkway is level.