Seal concrete joints - you should know that

Joints can assume different functions in concrete. In the case of concrete floors, joints must even be installed compulsorily and subsequently to avoid tearing the floor. What else you should know about concrete joints and their sealing, you will learn in detail in this post.

Different types of joints

Joints in concrete can be connecting joints on the one hand, and expansion joints on the other.


Connecting joints can be found everywhere, where different building materials meet. This can for example be the case between concrete and other building materials when a concrete floor meets a brick wall. But also a door frame connection to the masonry requires a connecting joint between different building materials.

Expansion joints

Exactly they are called "joints for recording movements". These include various joint constructions:

  • expansion joints
  • contraction joints
  • settlement joints
  • Dummy joints and press joints
  • Construction joints due to time interruptions during concreting, which may occur intentionally or unintentionally

Each construction is executed in a special way. For example, joints in concrete must always be frictionally locked if they are expansion joints. Only in this way can it be guaranteed that they can actually fulfill their task.

Specialist company for concrete restoration

In concrete construction, the joint construction and sealing is usually carried out by specialist companies. As a home improvement, both the expertise and the right tool (concrete cutter, etc.) are lacking.

Expansion joints are installed in large concrete floors to allow movement of the concrete in case of temperature changes and movements of the components (statics). Without these expansion joints, the concrete would break. Expansion joints can only be avoided with very small concrete floors.

Concrete must also be provided with joints along the edges of other components. They must be adjusted in their width and sealing the occurring, different sizes forces of both components.

But especially with connecting joints, the seal is also important to prevent the penetration of corrosion-promoting pollutants or the ingress of water. Failure to perform a proper joint seal can very quickly lead to severe damage to the structure.

When building with prefabricated concrete parts, joint sealing by a specialist company also plays an important role in statics, noise and heat protection and in building preservation. Such seals are a highly complex task and their execution requires professionalism and expertise.

Applicable regulations

Important regulations for the repair and sealing of joints can be found in the ATV DIN 18349 and in the DIN 18540. However, not all types of joints are treated here, and not all the methods used today are presented. For example, in practice, expansion joints made of elastomer are often used in different ways.

Crack injection

In the case of crack damage to components, especially of concrete, a crack compression is often used for the renovation. Also, this is actually a joint seal - but an unwanted (crack) joint. It can be made either tight or non-positive, depending on what the statics of the building requires.

Tips & Tricks

A correct and effective joint sealing in concrete is only given to an experienced specialist company. From self-tests with concrete spatula or similar measures should be taken in any case distance.

Video Board: Concrete Expansion Joints and using Sika correctly