Black tub

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As Black pan is made of thick bitumen coating , bitumen or synthetic resin sheets produced in the bottom located sealing referred to when all erdberührenden components of a Bauwerkes (pressure) encloses waterproof. With the appropriate design, the black tub can be used if the basement rooms are below the groundwater level .

Although the black tank is now being replaced by high-quality and inexpensive alternative designs in some applications, it is still widely used.

Nowadays, the production of a white tank made of waterproof concrete is often preferred, as this technology has now matured and guarantees an almost equivalent seal. A disadvantage can be that the white tub, depending on the quality of the concrete and construction, allows a small amount of moisture to be exchanged between the ground and the basement. Some experts see this as a fundamental structural flaw.


This seal is usually on the outside of the building. A protective layer is provided between the seal and the soil, which can consist of gravel , perimeter insulation or drainage panels (similar to foam polystyrene panels ). Before the production of the bottom plate is usually above the lowest capillary breaking layer first a thin subbase provided of concrete, to which the seal can be applied. Special care is required here, as subsequent renovation is time-consuming.

The outside of the walls is sealed with bituminous products or waterproofing slurry, the waterproofing must be carefully connected to the horizontal sealing plane under the floor slab. As a rule, the basement walls are then insulated using pressure and moisture-resistant insulation panels .

Alternatively, pressure-resistant insulation boards, e.g. B. PE-HD (Polyethylene High Density), which are then protected from the ingress of moisture by loosely laid plastic sealing membrane. A protective layer that is again required here between the sealing level and the ground means a somewhat increased effort. The advantage, however, is that the insulation value of the insulation installed on the dry side is not impaired by penetrating soil moisture.

Since with this design moisture from the room air in the basement can diffuse through the outer wall into the insulation, either the insulation layer should be made diffusion-tight or a ventilation level should be provided on the outside or, if necessary, on the inside of the insulation layer. Since there is only a very small amount of moisture, little ventilation is sufficient to dissipate it. If, however, this is not done, the moisture will accumulate in the insulation layer, which means that the advantage over the external insulation is lost again. In the worst case, the condensate can collect at the foot of the wall and cause moisture damage here after a long period of time.

Norms and standards

  • DIN 18195: 2017-07 - Sealing of buildings
  • DIN 18533-1: 2017-07 - Sealing of components in contact with the ground - Part 1: Requirements, planning and execution principles
  • ATV DIN 18336 - sealing work
  • Guideline for the planning and execution of waterproofing with plastic-modified bitumen thick coatings


  • Jürgen Weber, Volker Hafkesbrink (Ed.): Building sealing in the renovation of old buildings. Procedure and legal approach . Teubner, Wiesbaden 2006, ISBN 3-519-00460-7
  • Karl Lufsky, Michael Bonk, Erich Cziesielski: Building waterproofing . 6th, updated edition, Teubner, Wiesbaden 2006, ISBN 978-3-519-45226-3
  • This is really how it is sealed . In Bautenschutz + Bausanierung (special print), Vol. 22 (1999), Part 1, ISSN  0170-9267

See also

Individual evidence

  1. Karl Lufsky, Michael Bonk, Erich Cziesielski: structural waterproofing , page 433
  2. Manfred Curbach: Position Paper of the German Committee for reinforced concrete to DAfStb guidelines "Water-impermeable concrete structures" - moisture through WU constructions , Berlin 2006 ( Memento of the original June 15, 2016 Internet Archive ) Info: automatically set the archive link is and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot /
  3. Deutsche BauZeitschrift (DBZ), Vol. 53 (2005), No. 10, Pages 79-80, ISSN  0011-4782