The ANELTEC bentonite joint is a joint based on sodium bentonite and organic binder, which is used for sealing construction joints of underground structures, and sealing non-mobile joints from any possible ingress of water . When in contact with water, the profile gradually increases in volume, ensuring waterproofing, once it is confined between concrete and concrete.

The joint expands by 200-300% in volume and resists a water pressure of 5 bar (50 m).

A typical application is in the waterproofing of construction and connection joints, on concrete structures located at water level. Integrated into concrete construction joints, the curb expands in contact with water sealing the structure.

The hydro-expansive waterstop bentonite joint provides a permanent sealing, guarantees total safety, excluding potential defects that may derive from conventional construction, as well as all losses deriving from water infiltration.

The ANELTEC hydro-expansive waterstop joint is available in size 20x25 and in size 20x10, and we also have special adhesives for fixing and mesh.



  • Waterproofing for construction joints.
  • Based on natural sodium bentonite.
  • Quick and easy to apply.
  • It does not wash away, even at maximum expansion.
Scarica la Scheda


bentonite joint

The ANELTEC bentonite joint is used as a sealant for construction joints. Once in contact with water, it expands and prevents infiltrations.

joint waterstop

Our bentonite joint is fixed with a special glue, or with nails.

bentonite waterbar

Our 20x25 bentonite joint is supplied in boxes of 30.00 m (6 rolls).

Bentonite waterstops are used extensively in the concrete and construction industries, as they provide an efficient means of sealing construction joints. The characteristics and peculiarities of the product are well known.

Even after repeated swelling cycles, our bentonite joint maintains a perfect seal thanks to its high rubber content, which helps to keep the product as compact as possible despite the large variations in volume.

The joint is fixed to concrete structures in the following ways:

  • with steel nails and washers, directly on the structure
  • through a pre-shaped, trapezoidal-shaped steel mesh open on one side only, to be used to favor the correct positioning of the bentonite joint, and prevent it from moving from the intended seat, especially in complex situations or on surfaces not perfectly prepared. Once the joint has been inserted, the mesh must be fixed to the concrete support using steel nails and washers every 20-25 cm.
  • with the special ANELTEC polymeric adhesive, with a sealing and permanently elastic action, specific for bonding gaskets, joints and curbs.

For the installation it is necessary to pay attention to the positioning, which must not be too close to the edge of the structure, to allow an optimal confinement (the ideal is to have a distance of about 12-13 cm). The connection between a roll and the next roll occurs simply by placing the end of one roll side by side with the beginning of the next, making sure that the two ends run parallel for at least 5-6 cm. The fastening by nailing must take place approximately every 25 cm.



The waterstop bentonite joint is used for:

• sealing vertical and horizontal construction joints of underground structures;
• sealing in all situations which allow for regular confinement;


Then find them by clicking here. You will be redirected to our PVC waterstop joints page.