How to Repair a Driveway Expansion Joint

A well poured concrete driveway should have expansion joints installed to prevent the concrete from rising or buckling. Over time, if the concrete expansion joint begins to degrade, you may experience excessive moisture damage, that will cause the slabs of concrete to shift.

Before beginning this project, you must purchase replacement expansion joints. These boards are made of material that will fill the gap between the slabs of concrete, but also accommodate the contraction and expansion of the concrete driveway. You will also need joint mastic to completely repair your driveway expansion joints.

You should also plan on repairing the expansion joints when the weather is temperate and at least 50 degrees. Check the weather forecast for a week where it is unlikely to rain to give the mastic a chance to cure. Do not drive over the mastic until it has cured according to the manufacturer's instructions.

Step 1: Chip out the old expansion joint using a cold chisel and a ball peen hammer. Often you will be able to drive the cold chisel into the expansion joint and pull out most of the expansion joint once the cold chisel is firmly lodged into it. No matter how you remove the material, you must chip away and discard any of the old material.

Step 2: Use a hand broom to carefully remove any debris from the newly exposed gap between the slabs of your concrete driveway.

Step 3: Clean the expansion joint with water and scrub brush or a pressure washer to firmly wash away any stubborn dirt.

Step 4: Place the new expansion joint board into the empty, cleaned gap. Use a hammer to push the expansion joint in between the slabs of concrete. Continue pushing the expansion joint down until it is ¾ inch below the surface of the concrete driveway.

Step 5: Apply a layer of joint mastic over the expansion joint board with a trowel. Smooth the joint mastic so it is flush with the surrounding surface.