Drainage on the outside of a cellar wall


The basement of a building is repeatedly threatened permanently and repeatedly from outside acting water. To prevent damage from backwater, drainage is created around the basement. In the case of incorrect dimensioning or structurally defective execution, corrections must be made, usually from the outside.

Soil, ground or condensation water

Every basement wall is potentially endangered by moisture. In the vast majority of cases, the cause of damp or wet walls is outside. However, other possible causes should always be considered.

A basement wall is not only endangered by water ingress. The prevailing and changing temperature contrasts of the walls, especially in unfavorable ventilation conditions, can also lead to the development of moisture from the inside. Typical is condensation, for example by drying laundry or heating.

Drying and draining

Always and in any case damp cellar walls must be dried and drained. The drying can also be done from the inside. When draining, the cause must be eliminated. A faulty and overloaded drainage must be rehabilitated from the outside.

In addition, and for internal causes, the sealing of the wall from the inside and / or an impregnation can be helpful. Not enough is the sealing only from the inside, which acts only temporarily and later possibly cause much worse damage.

Tasks of drainage

Common building drainage on a basement wall consists of a combination of gravel layer and drainpipe. The gravel distributes the flow of water and the drainpipe diverts the water to more distant and deeper soil regions.

  • Derivation of normal groundwater supply
  • Derivation of groundwater
  • Derivation of precipitation and condensation water

Important component drainage is an inspection opening. Only through them is the freedom and cleanliness of the drainage routes to check. A regular check and, if necessary, cleaning avoids that the actually functioning drainage in front of the basement wall fails because of blockage.

Structurally required, but in many cases not met, is the use of blue or gray bar tubes instead of yellow elastic and flexible roller tubes.

Tips & Tricks

If your cellar wall has become damp, materials and materials may be faulty in addition to building-physical defects in the drainage. A non-uniformly applied bituminous layer or holes in the order form water entry ports.

Product Image: Marina Pousheva / Shutterstock


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