Waterstops & Joint Sealing

The joints in a concrete structure are the most common point of water ingress, and they are the most difficult to repair. A construction joint is a joint between two pours of concrete, and it is a natural point of weakness because the two pours are not fully bonded. An expansion joint is a joint that is designed to allow the structure to move, and it is a point where the waterproofing has to be able to move with the structure.

The first step is to understand the joint. We need to know what the joint is, what the movement is, and what the water pressure is. We also need to know the condition of the joint — whether it is clean, whether it is cracked, and whether it is leaking. The repair is different for a construction joint and an expansion joint.

For a construction joint that is leaking, we use a waterstop that is installed in the joint. The waterstop is a PVC or rubber profile that is cast into the concrete, and it blocks the water path through the joint. The waterstop is installed in the joint, and it is the most effective way to stop the water in a construction joint.

For a joint that is already leaking, we use a polyurethane injection. The polyurethane is injected into the joint under pressure, and it expands to fill the joint and the cracks around it. The polyurethane is a hydrophilic material that swells in the presence of water, so it is the ideal material for a joint that is leaking.

For an expansion joint, we use a movement joint system that is designed to accommodate the movement of the structure. The joint is filled with a flexible sealant that is backed by a foam, and the sealant is designed to move with the structure. The sealant is also protected with a cover that prevents the water from reaching the joint.

We also look at the details. The joint is often leaking at the intersection with the wall, the floor, or the penetration, and the details are the most common point of failure. We detail the joint at the intersections, and we make sure the water is stopped at the joint.

The result is a joint that is sealed, a joint that is watertight, and a joint that is protected. We document the system, we provide the specification, and we stand behind the work.