The method for waterproofing tunnels with KOSTER 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. 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 KOSTER KB-Pur IN 1 and permanently sealing with the elastic resin KOSTER KB-Pur IN 2. Small leakages or whole walls which are being penetrated by water can be sealed with KOSTER KD 2 Blitz Powder. To waterproof the entire surface from the negative side, KOSTER NB 1 Grey is applied to the dry and solid substrate. After KOSTER NB 1 Grey has hardened, the crack bridging coating KOSTER 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.