A subsidence drain survey is a specialist CCTV inspection commissioned as part of investigating building movement attributed to subsidence, heave or related ground instability. Defective drains that leak over time can wash away supporting soil, particularly on shrinkable clay subsoils across London, making drainage a recognised contributory factor in many subsidence claims. The survey covers the lateral and private drainage in the vicinity of the affected building, with defects graded against the WRc Manual of Sewer Condition Classification under BS EN 13508-2. Engineers usually work alongside structural engineers and arboriculturists, providing a written report and footage as documentary evidence for the insurer. Findings inform the repair strategy, which may include cured-in-place lining under BS EN ISO 11296, patch repair or excavation under BS EN 1610.
Subsidence drain survey
Specialist drain survey carried out as part of investigating subsidence-related building movement.
