We at Cockrams Surveying undertake ‘look see’ CCTV drain scans (where access permits) on our intermediate and full building surveys. We have always considered this is necessary on older properties as defective drains can wash out the ground and cause foundation movement. Blockages in drains can also expose occupants to significant health risks including rodents penetrating the drains and thereafter habitable accommodation.
We have found that at least six out of every ten drains that are scanned are found to be defective including asbestos impregnated pitch fibre conduit and broken clay or salt glazed pipework. Route ingression is also a serious problem.
We recently undertook a survey on a bungalow in Truro. Our external inspection confirmed that the path beside the property had subsided significantly. The cast steel access cover was raised and a visual examination of the pipes etc. did not reveal any significant defects. The toilet was also flushed and the water ran away efficiently with no sign of any defect. The kitchen tap, which is a continuation of the sewage pipe run that is a continuation of the foul pipe from the bathroom and WC, was also run and no water at all was seen to discharge into the access chamber. The bath taps and sink were also run and again no foul water was seen at all although water was noted to flow into an adjacent drain trap. The ‘look see’ scan was undertaken towards the road and the mains system where it was noted that there was significant misalignment of pipework which would allow foul water to saturate the surrounding ground. The scan was then continued up towards the kitchen where it was noted that the pipework had sunk so badly that it was flowing backwards, which is why no water from the kitchen, bath or sink appeared within the main inspection chamber. Moreover, it was saturating into the surrounding ground through several broken and leaking joints. The path and all the pipework will need to be excavated and replaced, which will be expensive.