Dachdichtbahnen: The big overview


There are as many options for sealing the flat roof as for covering a pitched roof. What types of roofing membranes are there, and which are best used where, tells you this post.

Bitumen or plastic

The most common web-based roof seals use either special bitumen membranes or plastic sheets.

In the sealing membrane made of (polymer) bitumen, the so-called bitumen roofing membrane, one can distinguish between two variants:
On the one hand, sheets of polymer bitumen modified with elastomers, and on the other hand bitumen roof sheets in which the bitumen is modified with thermoplastics.

There are several options for plastic tracks:

  • Polyolefin plastics (FPO / TPO)
  • PVC, also known as PVC-P
  • ECB webs (ethylene copolimerisate bituminous membranes), which, however, are counted among the plastic webs
  • PIB (polyisobutylene)
  • EVA or UAE membranes (ethylene vinyl acetate copolymer)
  • PE sheets, which are usually made of chlorinated PE material (PEC)

Synthetic rubbers

Equally important are rubber materials. Synthetic rubber occurs in roof sheeting in the following forms:

  • EPDM (ethylene-propylene-diene monomers)
  • Chlorosulfate-based polyethylene (CSM)
  • Nitrile and butyl rubber sheets (NBR, IIR), less common

EPDM foil

Especially EPDM foils are often used today as an alternative to flat roofs with bituminous membranes.

The advantages are above all:

  • extremely high UV resistance (just the weak point in bitumen waterproofing)
  • very low weight
  • high wind suction strength
  • very high temperature resistance (-45° to + 130° C)
  • no damage due to acid rain, oil-resistant
  • easy to assemble yourself (while laying
    Bituminous membranes not only special equipment but also expertise is needed)

Individual manufacturers certify that the EPDM film has a lifetime of up to 50 years. Within this time, the film is completely maintenance-free, and the roof also accessible. With a price per square meter starting at around 10 EUR per m² (plus the costs for the adhesive), the cost-benefit calculation is also much better than with bitumen-welded roofing.

The foil is available with a width of up to 12 meters. Thus, even larger flat roofs are easily covered with the film. It is important to pay attention to the addition LSFR in the execution - that means secured against flying fire. In Germany is the duty.

Roof waterproofing membranes with integrated photovoltaic system

Solar roofing membranes may be a way to use a conveniently located flat roof to generate electricity (such as the roof area on the carport). As a rule, these are plastic roofing membranes with flexible, embedded solar modules. The solar modules are connected in series, the lines are fully encapsulated. In high-quality design, the solar modules are usually built in three layers to use different wavelengths of sunlight for comprehensive power generation can.

Current efficiency in the flat roof

The advantage of the flat roof system is that non-sloped roofs are very little dependent on the orientation of the roof surface in order to achieve a high current efficiency. A flat roof will provide no more than 12% less electricity than an optimally oriented and sloped roof, regardless of the orientation of the roof. A base of mineral plates is usually recommended.


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