A waterstop is a material inserted in concrete that has the sole aim of preventing water from passing through the joint.
To put it another way, it’s not an elastomeric sealant applied to a joint’s exposed surface. Waterstops cannot prevent water vapor or capillary moisture potential from migrating through a concrete slab to safeguard the flooring system (such as hardwood or tile) from adhesion failure or deterioration beyond the junction. Waterstops are also unable to prevent water infiltration through fissures in the concrete caused by building settlement or live load deflection; for these difficulties, specifiers and contractors can use waterproofing membrane systems, vapor retarders, and other construction items.
It is critical that the waterstop is made from high-quality raw materials and is free of flaws. Many different material kinds and profiles are available for different uses and situations, therefore the specifier must choose waterstops that are appropriate for all of the joint conditions, ideally with manufacturer consultation.
Water penetration into below-grade concrete buildings is most likely to occur at joints created between adjacent concrete casts and where mechanical parts penetrate the concrete. Waterstops are typically specified and built at every joint in the concrete below grade to prevent this from happening.
To protect below-grade elements of a concrete structure, a waterstop put in concrete joints is an integral component of an overall waterproofing design. The use of these items in construction joints (also known as “cold joints”), whether with or without a positive-side waterproofing membrane, is a smart design practice for building foundations. To put it another way, the waterstop can be a belt-and-suspenders strategy to keeping the occupants and owner dry.
Water, which is present under intermittent or constant hydrostatic pressure, is very likely to infiltrate through the concrete joints in below-grade constructions. As a result, waterstops are employed on a range of concrete structures as part of the overall waterproofing protection, including:
Subway, automobile, and pedestrian tunnels; parking structures; water and sewage treatment facilities; and canals, locks, and dams are all examples of underground constructions.
When most construction professionals think of a ‘waterstop,’ they usually think of a 102 to 305 mm (4 to 12 in.) wide dumbbell or ribbed profile extrusion of thermoplastic or rubber material put in a concrete joint. Polyvinyl chloride (PVC) has been the most extensively used waterstop since the 1950s. Because of their ease of welding and natural resistance to groundwater and typical wastewater treatment chemicals, these items have been used. To prevent water infiltration through joints in concrete structures, a variety of myriad metal, plastic, asphaltic, and hydrophilic materials with various compositions and profiles are now used.
Read more: What is waterstop?