Tunnel waterproofing

Sealing membranes for tunnel waterproofing are available with and without signal layer.
Proper tunnel waterproofing is one of the most cost-efficient ways to extend the service life and improve the safety of such structures. Penetration of water into a structure poses a hazard to the construction material due to the freezing and thawing cycle. Water accumulating in cracks freezes and enlarges the existing cracks. Preventing water from accumulating and freezing on the road surface improves overall safety.

Each tunnel builder is aware of the problems involved with achieving proper tunnel waterproofing. The building authorities' pertinent provisions are particularly strict. The concept of solid sealing has proven sufficient in this regard, as the formation of cracks due to the cooling of concrete and later rock deposits cannot be avoided.

Flexible sealing membranes are used for applications in closed structures for more than 25 years now and play an essential role if absolute leak-tightness of the insulation is required.


Tunnel structure requirements are determined by environmental factors such as moisture, water pressure and other conditions. Tunnel lining has to be in accordance with these conditions. The installation depends on how the work is to be carried out (protection, sealing system, drainage and substructure) and on the type of substructure treatment.

The sealing membrane's properties shall address these requirements e.g. in terms of high resistance against hydrostatic puncture, high resistance against chemicals such as salts and acids, good ageing properties and resistance against other environmental influences. In any case, the sealing membrane must be characterised by good weldability for hot wedge and hot air welding techniques.

Always use a protective layer (geotextiles) to prevent sealing membrane damage during or after installation.

The proper installation is carried out with a frame at the bottom at the tunnel - with the sealing membrane either being rolled out from side to side or from the highest point on each side.

The sealing membrane is always installed together with geotextiles and fastening elements. In most cases, a seam including a test channel is used. The fastening elements are used to fasten geotextiles to the tunnel structure with nails and also serve as a primary fastening element in sealing membrane welding. Then the sealing membrane is joined with overlapping seams.

Tunnel sealing membrane with signal layer BTU / BTUS

Fields of application:

  • Tunnel lining membranes
  • Homogenous sealing membrane
  • with and without signal layer
  • not UV-stabilised

Colour: black or black with light-yellow signal layer
Thickness: 1.5 mm and 2.0 mm
Width: 2.0 m


  • Resistant to rotting
  • Root-resistant to DIN EN 14416
  • With signal layer
  • not UV-stabilised
  • Weldable
  • Free from lead and cadmium
  • not resistant against bitumen, oil, Diesel and other solvents
  • not resistant to contact with other plastics, e.g. polystyrene hard foam