Joint sealing The application of a flexible, waterproof sealant into sidewalk expansion joints to prevent water from seeping into the subbase.
Water is the number one enemy of concrete. If water seeps through open sidewalk joints, it will wash away the supporting soil or freeze and expand, cracking the concrete from below. NYC DOT specifications require that expansion joints be filled with joint filler material and properly sealed to protect the sidewalk's subgrade from water damage.
Frequently Asked Questions About Joint sealing
What is joint sealing?
Applying flexible waterproof sealant into sidewalk joints so water cannot reach the subbase.
Why does water in joints matter?
Water washes out supporting soil and freezes and expands, cracking the concrete from below. It is the leading cause of sidewalk failure.
Is sealing required?
DOT specifications call for expansion joints to be filled with joint filler and properly sealed.
How often should joints be resealed?
Whenever the sealant has hardened, shrunk or pulled away from the joint faces, which is typically visible on inspection.