Bitumen thick coating

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The bitumen thick coating is a structural designation for multilayered layers of polymer-modified bitumen (PMB) - until 2017 referred to as plastic-modified bitumen thick coatings (KMB) in Germany and today polymer-modified bitumen thick coatings (PMBC) - such as B. polymer bitumen and elastomer bitumen . These were developed as a supplement to the well-known and long-standing sealing systems for building waterproofing made of foils or bitumen sheeting (“ black tub ”).

In the case of thick coatings, the requirements of DIN 18195 are achieved through the requirement-related ( load case ) layer thicknesses .

Polymer bitumen

Polymer bitumen (PmB) are industrially produced mixtures of bitumen with polymeric plastics (e.g. thermoplastics such as PE , PP or PVC ) which are intended to increase the " plasticity range " and improve resistance to chemical influences. Compared to conventional road bitumen, they have the advantages of lower brittleness at low temperatures, higher resistance to deformation and better elastic recovery after physical loads.

Polymer bitumen (PmB) is also used for open-pored and gravel-rich asphalt surface courses , such as those used to reduce the risk of aquaplaning and also for so-called whispered asphalt .

Elastomer bitumen

By adding elastomeric plastics (e.g. polyurethane ), elastomer bitumen enables the coating to absorb any cracks that may appear in the substrate. It is therefore mainly used as a thick coating in the basement area and also for roofing and waterproofing membranes.

Coatings of this type are applied using a spatula technique to protect against penetrating moisture, depending on the load situation, as a vertical and / or horizontal wall seal on the underground basement walls.

Insert forms

These coatings are used in various components and processing forms.

  • one or two-component bitumen-plastic emulsions
  • One-component thick-film compounds based on bitumen-plastic emulsions
  • Two-component thick-film compounds made of plastic-based (modified) bitumen emulsions and reaction components

Load cases

  • Load case 4 - Soil moisture refers to water that is always present in the ground, bound by capillaries and that can also be transported against gravity by capillary forces (e.g. natural soil moisture, suction water, retained water, capillary water). DIN 18 195 Part 4 regulates further details.
  • Load case 5 - Water pressing from the inside describes water that can develop on ceiling surfaces, e.g. B. in damp and wet rooms or on balcony areas that are not inhabited. Swimming pools and exposed balcony areas, for which separate regulations apply, are explicitly excluded. DIN 18 195 Part 5 regulates further details.
  • Load case 6-1 - Non-pressing water refers to the surface and seepage water in dripable liquid form that does not exert any significant or only temporarily a low hydrostatic pressure on the waterproofing . DIN 18 195 Part 6 Point 9 regulates further details.
  • Load case 6-2 - Pressing water refers to water that exerts permanent hydrostatic pressure on the waterproofing from the outside. This pressure in turn depends on the height of the water column (e.g. groundwater , suction water or spring water ). DIN 18 195 Part 6 Point 8 regulates further details.

Subsurface requirements

All substrates must be dry, firm, load-bearing, dust-free and completely free from contamination (e.g. tar paints or similar) and the masonry must be fully jointed (horizontal joints ) and flush. If the butt joints are missing , they must be pretreated according to the product manufacturer's instructions .

processing

Today's emulsions can be processed cold and, in contrast to the tar- pitch seals used previously, are ready for use without time-consuming and dangerous heating. Depending on the consistency of the material , processing is carried out using a roller, brush, spray or spatula method, with one or more applications. In some cases, bituminous primers or primers may be necessary and are recommended by the emulsion manufacturer.

When applying the emulsions, it is essential to ensure that the substrate is dry, as water impairs the adhesion and also forms an unwanted separating layer , which would cause the coating to leak. It should also be noted that existing cracks in the substrate (e.g. shrinkage cracks in base plaster) can only be bridged up to a maximum width of 2 mm. Larger cracks must be filled in flush beforehand.

The thickness of the dry layer to be applied is at least 1 mm in load case 1, at least 2 mm in load case 2 and at least 4 mm in layer thickness in load case 3. After a drying time of 2 to 3 days, a protective layer (usually a film ) is applied to the sealing layer according to the manufacturer's instructions.

The protective layers applied depending on the load case permanently protect the building waterproofing from damaging influences of a static, dynamic or thermal nature.

When filling the area surrounding the masonry, care must be taken to ensure that the protective layer or even the sealing layer is not damaged (e.g. by large stones or debris ).

Qualification (formerly KMB certificate, today sealing certificate PMBC)

In September 2000, the course "Manufacture of seals from plastic-modified bituminous thick coatings" (KMB) based on DIN 18195 was launched on behalf of the training advisory board of the same name and for the first time as a pilot course at the training centers of the building trade e. V. (BZB) in Krefeld. The RILI is the essential basis of the training. The course in theory and practice concludes with a nationwide proof of qualification, the "PMBC certificate". The training is offered at various training centers in the building trade and the construction industry throughout Germany. The course concludes with an examination.

Legal considerations

When a change to DIN 18195 was introduced in addition to the older production of building waterproofing in the form of a "black tub" using plastic sheeting, a dispute arose as to whether the bitumen thick coating, in addition to the use of plastic sheeting, complied with the recognized rules of technology . The case law of the higher regional courts came to different results. The Bamberg Higher Regional Court took the view that the thick bitumen coating, despite being included in the DIN standard, did not comply with the recognized rules of technology. In contrast, the Higher Regional Court of Schleswig and the Higher Regional Court of Hamm took the view that thick bitumen coatings, if properly carried out, would comply with the recognized rules of technology. The Federal Court made a decision on 15 June 2000 the question of whether bituminous thick coatings generally correspond to the rules of the art, open. It was made clear by the Federal Court of Justice that an incorrect application of the thick coating represents a defect . In the meantime, the OLG Bamberg has also decided that, from its point of view, there is only a violation of the recognized rules of technology in the event of an improper implementation of this thick bitumen coating. The Hamm Higher Regional Court corrected its old judgment on August 14, 2019 (file number 12 U 73/18) and does not see the combination seal consisting of waterproof concrete floor slab and thick bitumen coating for the water load cases "accumulating seepage water" and "pressing water" as not general recognized rules of technology.

See also

literature

Web links

Individual evidence

  1. Training Advisory Board
  2. OLG Bamberg BauR 1999, 650 = NJW-RR 1999, 962; IBR 1997, 417; so also Kamphausen, yearbook construction law, 2000, 218 (227f.)
  3. OLG Schleswig BauR 1998, 1100 = NJW-RR 1998, 171 = IBR 1998, 149; OLG Hamm BauR 1998, 1119 ( guiding principle ) = IBR 1998, 337; so also Jagenburg, BauR 2000, 1060; Jagenburg / Pohl, BauR 1998, 1075 (1077 f.)
  4. BGH, judgment of June 15, 2000, Az.VII ZR 212/99 full text at openjur.de (accessed August 14, 2012)
  5. OLG Bamberg IBR 2003, 407
  6. Oberlandesgericht Hamm, 12 U 73/18 of August 14, 2019, accessed on August 25, 2020