How to Waterproof a Well

Wells have served people for thousands of years, built for various purposes. While their design has evolved over the centuries, they remain an essential tool in our daily lives. A well is an artificially created, drilled, or excavated opening that reaches the water table. Most commonly, wells are constructed from reinforced concrete rings stacked on top of one another. These rings are often joined using basic cement mortar, without considering waterproofing.

Adverse temperature changes and, more importantly, the harmful effects of salts in the water can damage the connections between the rings. This can lead to:

• Contamination of the water with sand, clay particles, and soil, which may contain chemicals harmful to our health.
• Over time, cracks in the rings, further compromising the well's structure.

It’s important to note that replacing damaged rings is significantly more expensive and labor-intensive than properly waterproofing the well during construction. Quality waterproofing can protect a well for many years, ensuring its durability and water purity.

A Well After Pumping Out Water

Case Study: Well Waterproofing

Problem:
Leaking joints between the concrete rings in a well and leaking pipe connections. Additionally, water seeps through the concrete layer at the bottom of the well.

1. Sealing Pipe Penetrations

To effectively seal pipe penetrations in a well, follow these steps:

1. Prepare the Area
   • Chisel around the pipe to create enough space for the application tool with a nozzle diameter of at least 1 cm.
2. Apply the Sealant
   • Use KOESTER KB Flex 200 and apply it tightly around the pipe, ensuring a minimum thickness of 8 cm in the barrier.
3. Finish the Surface
   • Leave at least 2 cm from the wall’s surface to properly seal off the sealant.
4. Close the Seal
   • Use KOESTER WASSER STOP or KB FIX 5, a quick-setting waterproof mortar, to finalize and secure the seal.

To ensure a durable seal around pipe penetrations in a well, start by applying a sealing slurry such as Bostik C514 Terra 1K (K11 Schlämme Grau), KOESTER NB 1, KOESTER NB Elastik, or Schomburg Aquafin 2K/MPplus—all certified by PZH for safety. Apply the slurry around the pipe penetration, extending 10–15 cm onto the surrounding surface and at least 10 cm onto the pipe itself.

Before applying the slurry to a PVC pipe, clean the pipe thoroughly and apply a primer for non-absorbent surfaces, such as Bostik A936, to ensure proper adhesion. Then, apply the first layer of the chosen waterproofing slurry and embed a sealing tape, like Bostik Sanitary Band, at the joint between the substrate and the pipe. This process creates a secure and long-lasting waterproof seal, effectively protecting the well from leaks and structural damage.

Sealing Before Applying the Slurry

2. Sealing Joints Between Concrete Rings in a Well

The joint should be chiseled into a dovetail shape. This method ensures that the sealing mortar is locked in place, preventing it from being pushed out of the joint, which could happen if the connection were merely widened.

For sealing, use Bostik Reno C788 Fill Turbo (Rapid 8), KOESTER Wasserstop, or KB FIX 5. After sealing the chiseled joint, apply a waterproofing band over the sealed area. Use only sealing slurries certified by PZH to ensure durability and safety. This process ensures a long-lasting and effective seal for the joints.

Creating the Waterproofing Band:

Clean the concrete rings thoroughly using a wire brush, ensuring a width of 15 cm above and 15 cm below the joint. Remove dust and debris, and dampen the surface before applying the first layer of the sealing slurry. Use Bostik  C514  Terra 1K ( K11 Schlämme Grau), KOESTER NB 1, KOESTER NB Elastik, or Schomburg Aquafin 2K/MPplus.

That's it! Remember, properly executed sealing will extend the lifespan of your well for many years. It’s worth investing in high-quality materials and skilled workmanship to ensure long-lasting results.

Completed Well Waterproofing