CCTV drain survey in Dudley: root ingress

What we surveyed

A CCTV inspection at a residential property in Dudley (DY1), covering 4 separate runs of pipework, 100 mm bore, foul and combined.

The system is polyvinyl chloride and vitrified clay.

Modern PVC runs, usually a later replacement or an extension to the original system.

Vitrified clay is what most pre-1970s drainage in the Midlands is built from. It is durable but brittle, and its short pipe lengths mean many joints – which is where almost everything goes wrong.

What the camera found

9 defects were logged and coded.

The worst section graded C on the Drain Repair Book scale.

Root ingress (4 observations)

Roots find their way in through the smallest opening in a joint, then thicken until they hold back everything moving past them. They are the most common single cause of repeat blockages in older clay drainage.

Distance	Code	Observation
0.90 m	R	Roots
1.70 m	R	Roots
10.30 m	R	Roots
11.00 m	R	Roots

_Distances are measured from the start of the run in which each observation was recorded, not from a single point._

Displaced and open joints (2 observations)

Displaced joints are where one pipe length has moved relative to the next. Ground movement and, across much of the Black Country, historic mining subsidence are the usual causes. Each step is somewhere solids can lodge and roots can enter.

Distance	Code	Observation
9.60 m	JDM	Joint displaced medium
10.80 m	JDM	Joint displaced medium

_Distances are measured from the start of the run in which each observation was recorded, not from a single point._

Water infiltration

Infiltration means groundwater is getting into the pipe. It loads the system and points to an opening that will not improve on its own.

Distance	Code	Observation
7.80 m	I	Infiltration

_Distances are measured from the start of the run in which each observation was recorded, not from a single point._

Cracking and fracturing

A crack is the stage before a fracture, and a fracture is the stage before a collapse. Catching one on camera is the difference between a patch liner and an excavation.

Distance	Code	Observation
12.80 m	CC	Crack, circumferential 06-12

_Distances are measured from the start of the run in which each observation was recorded, not from a single point._

Broken pipework

Broken pipework does not repair itself and will keep catching debris until it is dealt with.

Distance	Code	Observation
17.20 m	H	Hole in drain/sewer 11-01

Outcome

---

CCTV drain surveys in Dudley · Blocked drains in Dudley