Substruck Ltd. was employed to investigate the cause of persistent blockages to a drainage system in Cork City. The drainage had been replaced in uPVC with well over ten years, but since then, the drains required consistent monitoring and rodding, much to the frustration of its owner.
On arrival, we opened the front chamber and to no surprise, it was blocked. We cleaned it by normal methods of rodding and on closer inspection, it was clear that the interceptor trap was the culprit. Interceptor traps are no longer installed due to much improvement in the design and construction of drainage systems, particularly from a ventilation point. Such traps can be a common cause of blockages, particularly if incorrectly installed.
The interceptor trap was incorrectly installed along its longitudinal axis. The correct installation method can now be considered ‘tricks of the trade’ and won’t be divulged on this site. However, the only remedy was the removal of the trap. The benching around the rodding eye of the trap had become eroded and water escape was clearly visible so a temporary repair was completed so the ground could dry out and make life easier.
After a couple of weeks, we returned and removed the trap. Working space was tight as the chamber was located close to the public footpath. Chamber walls were repaired locally, and the benching was redone. After a few months, we contacted the homeowner who had been monitoring the situation and everything was found to be flowing nicely.