We were called to an office in central Dorchester to investigate the cause of a repeat blockage in the foul manhole just inside the door of a small rear room.
Using CCTV the fault was identified as a partially collapsed drain in the small rear courtyard. This was only a couple of metres square so digging was very awkward and had to be undertaken very carefully by hand but after a short time the broken pipe was found. Also found was a small hole. Looking in the small hole we could see what appeared to be circular block work. Holding the camera in further it was clear that we had found a very deep Well.
This was in the centre of the town and in the middle of a group of buildings! It was dangerous to dig back any further so a section of UPVC pipe was positioned between the two pieces of the old Salt Glaze pipe and a Polyurethane “Brawoliner” installed from the manhole, through the plastic and on down to the submain repairing and sealing all in one go to form a new drain.
The local Authority Archaeologists were called to inspect and log the site before we repaired the hole in the Well and back filled the excavation. We believe that the old pipe had cracked causing leakage that weakened the wall of the Well and when that gave way the leak washed the pipe support away causing the pipe to drop causing the blockages and a rapid escalation of the problem.