How to Ensure Watertight Metal-Sheet Waterstop Connections?
The importance of construction joint connections.

Metal-sheet waterstops are used to waterproof construction joints before or during the concrete cast. Over the years, we have seen various ways of connecting the metal-sheet waterstops, but which connections are watertight, and which connections should be avoided?

Below we share tips on how to achieve a watertight connection with metal-sheet waterstops.


  • Forgetting to add connection brackets or too few of them - easier for concrete to push the waterstop connection apart during casting and water to penetrate through. 
  • Making too-long overlaps (over 20 cm) - high risk of water pressing through the gap between the long overlap. 
  • The metal-sheet waterstop is not straight. For example, stepped on - a curved waterstop can no longer guarantee its function.
  • Installing too close to reinforcement - air pockets between the rebars and the waterstop, leak risk. 
  • Waterstop is not embedded enough in the concrete or too deep inside the concrete.

These reasons are generally due to absent-mindedness or carelessness. However, they can easily be prevented by being more attentive and following the given guidelines.

Correct installation:

  • The proper overlap is 5-10 cm and ideally secured with 4 brackets (2 at the bottom and 2 at the top). 
  • The network of waterstops in the structure must be connected continuously without disconnection. 
  • Do not damage the waterstop.
  • The depth of the seam sheet installation must be at least 3 cm inside the concrete.

In Conclusion 

It is important to remember the basic principles of installation. First, overlaps must be glued together to create a full-surface connection between the two waterstops (over the entire overlap length). Connection brackets must be installed so that there is no wedge-shaped gap at the joint of the waterstop where concrete can press in during cast. Waterstops can only rest perpendicularly to the reinforcement. Any horizontal contact between the metal-sheet waterstop and rebars will impair the waterstop function by creating air pockets through which the water has easy access. Avoid damaging, bending, crushing, and stepping on the waterstop.

In Primostar's selection, you can find WPM® metal-sheet waterstops made in Estonia to waterproof construction joints. You can choose the WPM® waterstop with your preferred coating (mineral, bitumen, with crystalline admixture) - in addition, the mineral coating is weather-resistant. Furthermore, it becomes homogeneous with concrete during the setting process.

Reimo Tsepkin

Export Sales

   +372 656 3162
   +372 5668 4201

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