Waterstops: Get to Know Your Options

man applying waterproofing agentIn a concrete structure, the joints are the most vulnerable to cracking and leaking because of water getting to them. Usually, this causes fungus and mould to grow and compromise the integrity of the structure. There are many waterstops available for use in construction joints, each with characteristics that make it suitable for specific applications.

For instance, a PVC waterstop, which is also the most common, works well in wet or rainy conditions. After the professional overcomes the initial installation challenges, the PVC waterstop can serve you for a long time. Besides PVC, there are other types of waterstops.


Bentonite is a hydrophilic waterstop made of clay. When bentonite comes into contact with water, it could swell up to 16 times. Consequently, it forms a compression seal on the joints, filling voids and cracks. However, bentonite must be kept dry after application, and before pouring concrete otherwise, it causes damage. Since bentonite usually needs replacement after a while, it is suitable for places that are not commonly exposed to water.

Metallic waterstops

A metallic waterstop can be made out of steel, copper, lead or bronze. The metals are installed like PVC. They are solid, making them suitable for heavy construction applications, such as in dams. They can also be used in areas with extreme temperatures.


Urethane is hydrophilic, so it swells when exposed to water, growing close to 350 per cent of its original volume. Urethane waterstops are easy to install and can be applied with a caulking gun. Urethane must be kept dry 24 hours after installation before concrete can be poured.

When choosing the type of waterstop to install, consider factors such as chemical exposure, joint movement, hydrostatic pressure and the joint type. A waterstop that performs adequately must be suited to all of those types. For instance, a moving joint could do well with bentonite due to its expansion characteristic.