For the best possible outcome, replacing the existing concrete allows for proper base preparation and paver installation.  However, it is not always necessary. You can install Paver Tiles onto an existing concrete patio, walkway, driveway or porch using thinset or masonry adhesive to get an installation that is cost effective and adds a beautiful new look and durability to an existing paved surface. Surfaces should be free from debris, major cracks, heavy settling and potholes.