In 1985 the 10.8 kilometer (7 mile) stretch of Hanzomon Subway was constructed several meters below grade. During initial construction a 1” (2.5 cm) rubberized sheet membrane was installed as specified by engineers to provide the waterproofing protection required. Within one year the membrane system had failed in several places and was allowing water to penetrate the tunnel.
The Krystol T1 & T2 waterproofing system was applied on the inside of the tunnel to effectively withstand hydrostatic pressure and stop water ingress. Shortly after installation of the Krystol Waterproofing System, the tunnel was dry and ready for the daily wear and tear of public transportation.