The method for waterproofing tunnels with KÖSTER products is based on a combination of negative side waterproofing and a liquid applied crack bridging waterproofing compound. The waterproofing layers cannot be infiltrated and the water will not move laterally between the layers as with membranes. The system does not need drainage. No water is being drained off the surrounding soil so the water table is not affected.
This system is suitable for tunnels built with closed construction techniques. Flowing water is stopped by injecting KÖSTER KB-Pur IN 1 and afterwards permanently sealed with the elastic resin KÖSTER KB-Pur IN 2. Small leakages or whole walls which are being penetrated by water can be sealed with KÖSTER KD 2 Blitz Powder. To waterproof the entire surface from the negative side KÖSTER NB 1 Grey is applied to the dry and solid substrate. After KÖSTER NB 1 Grey has hardened the crack bridging coating KÖSTER CFR 1 is applied to the waterproofed and dry substrate. Finally the system is covered with another layer of concrete. The waterproofing is sandwiched between two concrete layers.
Always adhere to the specifications in the respective Technical Guidelines.