Crack Injection / Flex Tape

In the case of a defective wall-sole connection (or joint) and cracks in concrete components that are exposed to major movements and deformations, conventional crack

deformations, conventional crack injections alone are often not a permanent solution against moisture ingress.

With our ISOTEC flexible tape system, we offer a long-term secure method to successfully seal these cracks and joints.

ISOTEC Flex Tape System - Elastic sealing

The problem: cracks in concrete components

Cracks form unwanted parting planes in the concrete structure and affect the tightness of the concrete component. From a crack width of > 0.2 millimetres, a crack in concrete components can be water-bearing. This can lead to corrosion of the steel reinforcement in the concrete or to water penetration into the interior of a building. In particular, the area of the wall-sole connection must not have any leaks, as otherwise water can enter the building unnoticed and this process is only noticed after some time, as the water initially collects unnoticed under the screed. In addition to the functional impairment, the moisture under the screed insulation layer provides the ideal conditions for microbial growth such as mould and bacteria.

A proven method of sealing cracks in concrete building components is ISOTEC crack injection. A special synthetic resin is pumped into the crack using a high-pressure process. It is characterised by its flexibility, impermeability to water and resistance to all types of moisture.

Flexband system against cracks in concrete components

ISOTEC crack injection provides a permanent, elastic and watertight seal of the crack up to a crack width change of approx. 10 percent. If larger deformations occur in the concrete component, the flexbands system is used in addition to crack injection. Our procedure for crack injection with the Flexbandsystem is as follows:

Leaky joints and cracks in concrete allow moisture to penetrate

The problem: Cracks and water-bearing joints

Many concrete structures, even though meant to be waterproof, at some point show permeable joints or cracks through which water may enter and cause moisture damage. If the building is not accessible from the outside due to superstructures, the damage needs to be repaired from the inside.

Injected special resin prevents water penetration

01 Injecting

Initially, we inject our special resin into the joint with a special pump through drilling channels prepared with injection packers. This way, by using our ISOTEC Flexband System sealing process, we prevent water from entering into the affected concrete structure.

The joint is roughened for better adhesion of the Flexband system

02 Preparation

For better adhesion, we roughen the concrete surface next to the joint or crack and remove the resulting dust. We mask the borders with duct tape as an exterior boundary for the Flexband glue bed to be applied.

Special flex tape adhesive ensures a perfect hold of the flex tape system

03 Adherence

We apply a special glue adapted to the Flexband system and centrically imbed the ISOTEC Flexband above the joint on the glue bed. We go over it once again with glue and then remove the duct tape from the sides of the glue bed to leave clean borders.

Our satisfied customers

Crack injection/flexible tape system in the Obermarktpassage Minden

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At ISOTEC we only use sealing material that has been verified to comply with the structural requirements. This applies to the material as well as to the machinery used for the processing of the sealing material.

Your advantages at a glance

  • No time-consuming uncovering of leaking concrete components from the outside necessary
  • Creation of a waterproofing success on the side facing away from the water
  • Thanks to its high elongation capacity, our ISOTEC flexible tape system can also be used for dynamic cracks
  • Generally approved system by the building authorities

Tight even with moving components

Our ISOTEC flex tape is made of a special plastic that is extremely elastic. With an elongation capacity of up to 400 percent, our ISOTEC flex tape therefore offers sufficient security to seal even dynamic cracks and component joints with larger movements permanently watertight.

We make expansion joints tight

Flexband system

Our ISOTEC flex tape system is not only used as a subsequent sealant for water-bearing cracks and construction joints in concrete components. It is also used in the frequently damage-prone area of expansion joints between two concrete components, which are often found in underground garages and large basement facilities.

Attention must be paid to this during crack injection/flexible tape system:

  • Sufficient pre-treatment of the concrete substrate in the area of the adhesive bed to ensure adhesion of the flex tape system to concrete.
  • The top layer of concrete must be removed by grinding and the grinding dust must have been removed.
  • The substrate must not be wet.

Our ISOTEC specialist companies and the employees are trained in the Flexband system and are skilled in practical processing. With regular further training, they are technically up to date in order to always offer customers the best technical solution.

Areas of application and experience with the ISOTEC flexbands system

The ISOTEC flex tape system has been used successfully for decades for watertight sealing on the side of concrete structures facing away from water. Since then, ISOTEC specialist companies have already applied several kilometres of sealing tape to countless concrete structures. All structures have been successfully sealed using the ISOTEC flex tape system. This also applies to buildings that are immersed up to twelve metres into the groundwater.


to the Flexband system

Download information about our solutions. In addition to overviews, you will also find further subsections or use cases here. We also provide GAEB service specifications for our business customers.



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Brochure Flexband system


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