How to Level a Sunken Section of a Sidewalk

Draw three drill holes with chalk in a triangle on the sunken section. The holes must be 12 inches in from the ends of the sidewalk, and evenly spaced about 3 feet apart or less. If the sunken area is small, make two holes instead of three.

Drill each hole through the slab with a concrete drill using a 2-inch bit.

Set a slabjacking pump on the ground beside the sunken concrete. Screw one end of a hose onto the pump and attach a 2-inch wide nozzle to the other end. Push the nozzle into the lowest hole until you feel resistance.

Stir slabjacking grout with a wooden stirrer and use a shovel to scoop it into the slabjacking pump. This type of grout is more cementious with special additives so it won’t shrink in freezing temperatures.

Pump grout into the lowest hole until the hollow space between the pavement and sub-base is filled. Move the hose to the next lowest hole and fill the remaining cavity.

Insert the hose in the first hole and turn the pump on. Once the cavity is filled with grout, the pump will pressurize the grout to raise the slab hydraulically. Continue pumping until the sunken area around the first hole rises one inch.

Rotate the hose into each hole and repeat until the sidewalk section rises to its original level.

Clean the drill holes of grout with a moist cloth, and fill the holes with stiff mortar. Pack the mortar down with a putty knife and continue adding more until it reaches the surface. Cut off the excess with the edge of the knife so the patched holes are level with the sidewalk.