Drain lining or digging: how to choose, and when no-dig will not work
No-dig repair saves the driveway, the patio and the garden. It also has limits, and a contractor who pretends otherwise is selling you a repair that will not hold.
Why digging costs what it costs
Excavating a drain is rarely expensive because of the pipe. It is expensive because of everything above it. A block-paved driveway, a stone patio, a mature garden or a tiled kitchen floor all have to come up and go back, and reinstatement routinely costs more than the drainage work itself.
That single fact is why trenchless repair exists. Working inside the existing pipe leaves the surface above it untouched.
What can be repaired without digging
Patch repair. A short resin liner installed over one defect and cured in place. Right for a single crack, displaced joint or badly made connection in an otherwise sound run.
Full lining. A resin-impregnated liner drawn through the whole length and cured to form a new pipe inside the old one. Where roots have been the recurring problem, this is what actually ends the cycle, because it seals the joints they were using.
Pipe bursting. Replaces the pipe entirely by pulling a bursting head through it, fracturing the old one outward while drawing a new one into the space. Suits runs too damaged to line, where there is room in the ground for the fragments.
When digging is the honest answer
- A fully collapsed section, where there is no host pipe left to line
- A pipe deformed badly out of round, so a liner cannot seat evenly
- Pitch fibre pipework, common in 1950s to 1970s property, which deforms into an oval and delaminates
- A run with no usable access point at either end
- A defect right at a connection that cannot be reinstated afterwards
Any contractor quoting a lining repair without having seen inside the pipe is guessing. That is how a job turns into a variation halfway through.
The step people skip
Lateral cutting. When a liner passes a branch connection it seals it over, and that branch has to be reopened with a robotic cutter guided by camera. It is a required step, not an optional extra. A liner that closes off a connection turns one problem into two, and the second one shows up as a flat that suddenly will not drain.
Ask specifically whether reinstating branches is included in the quote.
Where this comes up in London
Anywhere the surface above the drain is worth protecting. We line a great deal in Richmond and Dulwich, where mature gardens and established planting make excavation genuinely destructive, and in Chelsea and Kensington, where the drive or the front lightwell above the pipe is stone and expensive to relay.