Repairing & Sealing Cracks in Concrete | QUIKRETE: Cement ...
Cut the tip of the nozzle at an angle with a utility knife matching the width of the crack and insert the tube into a standard caulk gun. NOTE: for cracks or joints over ¼ inch, a Backer Rod should be placed in the crack before applying the sealant. Step 4c Move the nozzle slowly along the length of the crack, allowing the sealant to settle.