Basics of
sealing tapes

Pre-compressed sealing tapes

Pre-compressed sealing tapes are polyurethane-based foam tapes that are impregnated with a water-repellent synthetic resin polymer. They are compressed and rolled up on a roll. After insertion into a joint, the tape expands and thus seals it.
The speed of expansion can vary greatly between summer and winter and also depends on the production date. The joint dimensions specified on the cardboard box must be adhered to, as this ensures that the compression is sufficient to guarantee impact­rain­tightness. In addition, great attention must be paid to the corner joint, as this is where most sources of errors occur during installation.


Incorrect dimensions and lack of attention in the corner joints are the biggest sources of error with this seal.

Anwendungsbild zum Abdichten des Dämmkeils über dem Element, um die Fassade abzudichten.
Anwendungsbild zum Abdichten des Dämmkeils über dem Element, um die Fassade abzudichten.
The example shows a tape in a pre-compressed state with a height of 8 mm. Fully expanded, this shows 40 mm. However, it may expand to a maximum of 20 mm in order to fulfil its function (driving rain tightness).

Application areas

They have many advantages, especially in old buildings and with exposed brickwork. Their ability to level out slight unevenness and their compatibility with all alkaline and mineral substrates allow a proper connection between the window and brick or clinker.

Tightness against driving rain 300/600

The compressed foam tapes are available in different qualities. The use of the different qualities depends on the area of application in relation to the type of property or the height of the building. For example, low impregnation grades with a performance of 150 Pascal driving rain tightness are sufficient for a pure decoupling application.

For a building height of up to 20 metres, sealing up to 300 pascals against driving rain is sufficient. For building heights over 20 m (up to 100 m), a tape up to 600 Pascal should be used. TEROSON PT ecoMAX 600 is the ‘all-rounder’ on the market and fulfils all requirements.


Determine the joint width and select the appropriate TEROSON PT joint tape and tape dimension in accordance with the specified tolerances. Auxiliary tools: Laying with the aid of a tape measure, spatula, scissors or knife.


Dust, sand and loose particles, such as building dirt and mortar residues, must be removed before application.

Expansion times

It is not only the ambient and substrate temperature that plays a role here, but also the belt’s own temperature. For this reason, the tape should always be stored in a normal climate. For expansion joints, the tape thickness should be determined taking into account the largest joint width to be expected.

After unpacking, first remove the leader strip from the roll, cut the beginning of the tape straight with scissors and apply immediately afterwards. To do this, remove the cover strip approx. 10-20 cm from the self-adhesive side of the tape (073 I 074).

Press the self-adhesive side by hand or with a spatula against the joint edge or the building element/mounting/shy;part, fix it in place and do not pull it to length. Then continue to remove the cover strip from the self-adhesive side according to the work progress. When cutting the tapes to size, add about 1 cm per running metre to compensate for any stretching. For wider joints, the tape should be set back 1-2 mm from the joint edge (075 I 076). After expansion, it adheres firmly to the edges of the joint. Unevenness is levelled out by the elasticity of the joint sealing tape.


As a general rule: heat accelerates expansion, cold slows it down.

Bild eines Fensterausschnittes mit Glattstrich zur Darstellung der Anwendung von Dichtfolien.
Bild eines Fensterausschnittes mit Glattstrich zur Darstellung der Anwendung von Dichtfolien.
Bild einer Verankerung des Blendrahmens zur Darstellung der Anwendung von Dichtfolien.
Bild eines Andrucks mit einem PE-Spachtel zur Darstellung der Anwendung von Dichtfolien.

An overview of a few advantages and disadvantages of compressed sealing tapes:Advantages

  • For exposed masonry
  • Good compatibility with mineral substrates
  • UV resistance
  • No mineral joint primer or dewatering necessary


  • Corner joint design difficult
  • Limitations in the joint dimensioning

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