Concrete Waterstop: How Does a Concrete Waterstop Works?

Water infiltration is a big problem for all types of construction projects. The most common locations of water entry into below-grade concrete structures are joints between adjacent concrete pours and locations where mechanical parts enter the concrete. To prevent this from happening, waterstops are frequently employed and positioned at every connection in the concrete beneath the surface. Waterstops are therefore crucial in the waterproofing of almost any concrete building.

Without a waterstop, water will quickly seep down into the walls of your basement or crawlspace. Once it reaches its limit, water can cause damage to the foundation. But, how does a waterstop work exactly? Let’s learn more.

What is a Concrete Waterstop?

Concrete waterstops are products designed to prevent water from seeping into between the concrete blocks. Unfortunately, many homeowners simply replace an old slab of drywall overtop of the existing concrete. But this isn’t ideal because it allows moisture to seep into the space below the surface of the wall, causing mould and rot. A concrete waterstop prevents moisture from getting under the surface of a slab. It sits directly above the concrete and creates a barrier between the concrete and any moisture outside. This means no more mouldy walls and rotting wood beams.

Waterstops are widely used for concrete slabs and concrete joints.

Waterstop for Concrete Slab

When installing a concrete slab, the edges of the slab are protected by adding waterstops. Water stops are placed around the edge of the slab to prevent water from seeping into the slab. These waterstops are typically made of plastic or rubber. In addition, some waterstops have grooves or raised areas that help keep the water away from the slab. Some waterstops even protect the bottom of the slab from moisture.

Waterstop for Concrete Joints

Waterstops are in high demand in areas with a lot of construction joints. The most frequent scenarios include: a transition zone between horizontal and vertical concrete parts, long wall areas that require multiple formwork for casting, and so on. Waterstops that are hydrophobic are built to prevent water from coming into the joints. They should be carefully installed along the centerline of the construction joints to prevent water from leaking out either side of the waterbar.

Concrete waterstops are incredibly simple and involve placing a thin layer of cement between two layers of concrete. Waterstops are used in a variety of structural applications, including:

  • Sewage and water treatment projects.
  • Tanks, channels, tunnels, and dams.
  • Locks and box culverts.
  • Various containment structures.
  • Bridge and deck abutments.
  • Wall and slabs.
  • Basements and foundations

What is the difference between a PVC waterstop and a swellable waterstop?

Waterstops may be diverse in form, function, and strength, making them suitable for different applications. Here’s a rundown of two most well-known types.

PVC Waterstop

PVC Waterstops are commonly used as an exterior waterproofing system for framing structures such as buildings, bridges, pipes, tanks and equipment. The main purpose of these systems is to prevent the passage of water while maintaining all other elements of the structure. A PVC Waterstop is made up of two components, the waterstop itself and the adhesive that secures it to the substrate. The waterstop is often referred to as “slip” as it provides a friction force against any movement of the surface.

Waterstops made of PVC are flexible and durable. They are essential whenever concreting is done in two phases (between the slab and the slab or the slab and the wall or the wall and the wall). They’re put inside of the reinforcing steel before concreting. The difficulty is in the installation procedure. It might take some time to properly insert the PVC into the junction, and it’s prone to damage during the concrete pour.

Swellable Waterstop

Swellable Waterstops are more environmentally friendly and offer superior performance in humid and wet locations. They are non-permanent, reusable solutions.

Swellable water stops do not degrade over time but rather absorb moisture from surrounding environments which allows them to grow and expand. This swelling causes the waterstop to form a tight seal, preventing further leakage. Typically, swellable waterstops are composed of a combination of modified bitumen, asphalt emulsion, natural rubber latex, synthetic rubber latex and various polymers.

How to Choose the Correct Waterstop?

It is very important to select the right waterstop for a structure. There are several types of waterproofing products available but not all of them are good choices. Some of these solutions contain harmful chemicals and other products can cost too much. So, before choosing any waterproofing solution, make sure to check out the following tips.

  • Choosing the right size: The thickness of the waterstop should match the depth of the concrete floor. Generally speaking, thicker systems have better performance than thinner ones. An additional benefit of thicker systems is that they can withstand greater environmental changes.
  • When choosing a waterstop, it’s important to consider the space that needs to be covered and how frequently the surface might undergo changes. Waterstops are designed to withstand certain weather elements and temperatures. Therefore, they can withstand exposure to sun, rain, snowfall, heat, cold, wind, etc. Be sure to select a waterstop that meets those specifications.
  • Choose the appropriate material for the application: The ideal waterstop depends on the structure’s type, degree of exposure, and construction technique. Waterstops come in a variety of forms and materials.
  • Always select a waterstop that matches the substrate being covered. For instance, if you’re using a waterstop over a concrete slab, choose a waterstop that has been tested on concrete.
  • Cost of installing a waterproofing solution

So, after checking out these tips, you should be able to choose the most appropriate waterstop solution for your construction works. Therefore, when selecting the waterproofing solution for your project, make sure you weigh out the pros and cons of the available options.

The main purpose of a concrete waterstop is to prevent water from penetrating under drywall or other types of finish material. When choosing between different materials, look at the pros and cons for each type before making your final decision. We offer a wide range of waterstops and accessories at Western Sydney Building Supplies, for your next concrete project. Browse our website for more products.

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