A PVC waterstopper, also known as a PVC waterstop, is a flexible and durable strip made of polyvinyl chloride (PVC). Its primary function is to prevent water from passing through construction and expansion joints in concrete structures. How It Works A PVC waterstopper is embedded within the concrete joints. When the concrete is poured, the waterstopper becomes a continuous, watertight diaphragm that spans the joint. Its flexibility allows it to accommodate movements like expansion, contraction, and other shifts in the concrete, while maintaining its seal. Uses and Applications PVC waterstoppers are essential in any concrete structure that is subject to hydrostatic pressure (water pressure). Common applications include: * Water-retaining structures: Reservoirs, water tanks, swimming pools, dams, canals, and sewage treatment plants. * Water-excluding structures: Basements, underground parking garages, tunnels, and retaining walls. * Other civil engineering projects: Bridges, culverts, and foundation slabs. Types of PVC Waterstoppers The type of waterstopper used depends on the specific application and the type of joint it is sealing. Some common profiles include: * Dumbbell/Flat type: These are used for construction joints where there is no significant movement expected. * Center bulb type: This design features a hollow central bulb that allows for greater movement. It is ideal for expansion joints where the concrete is expected to expand, contract, or move laterally. * Ribbed type: These have ribs along the body of the waterstopper, which provide a better grip and a more effective seal with the concrete. Waterstoppers can also be classified based on their placement: * Internally placed: These are positioned in the middle of the concrete structure and are the most common type. * Externally placed (or 'rear guard'): These are installed on the exterior face of the concrete, often on the bottom end of the structure. Installation Proper installation is crucial for the effectiveness of a PVC waterstopper. Key steps and considerations include: * Placement: The waterstopper is installed before the concrete is poured. It is typically secured to the reinforcing steel (rebar) to ensure it stays in the correct position.