When a drain pipe fails in London, you have two main choices. You can dig it up and replace it, or you can reline it from the inside without a trench. The pipe may be cracked, full of roots or collapsed. Relining has changed what is possible over the past decade. Still, it is not always the right answer. Here is how to choose.
How Pipe Relining Works
Pipe relining is also called no-dig drain repair or CIPP (cured-in-place pipe). We push a flexible felt or fibreglass liner into the damaged pipe and cure it with resin. The cured liner forms a smooth, jointless new pipe inside the old one. It seals cracks, bridges offset joints and blocks the gaps that roots use.
The job starts with a CCTV survey of the pipe. We then jet the pipe clean and prepare the liner with resin. We insert it by pulling it through from one end or by inverting it with air pressure. Hot water, steam or UV light cures the resin, depending on the system. A second CCTV run confirms that the liner sits correctly and seals well.
The lined pipe has a slightly smaller bore. The smooth surface usually makes up for this, because water meets less friction. Manufacturers typically quote a design life of 25 to 50 years, depending on the system.
Our pipe relining service covers the full process from survey to the final inspection.
When Relining Is the Right Choice
Relining works best when the pipe is damaged but still in place. It may have cracks, roots or offset joints. It must not be collapsed or missing sections. We also need access at both ends, or at one end with a back exit. The bore must be wide enough for the liner to pass.
Root intrusion with sound pipe walls. Roots may enter through cracked joints while the walls stay sound. Jetting clears the roots first. The liner then seals the cracks, so the roots cannot return, although the pipe must stay sound.
Cracked clay pipes in London gardens. Soil movement cracks Victorian clay pipes, along their length or around them. These pipes suit relining if the cracks have not turned into a collapse. London Clay is the most common cause. See our post on why London clay soil damages drains.
Runs under gardens. A damaged section may lie under a mature garden, patio, driveway or outbuilding. Digging there does a lot of collateral damage, while relining leaves the surface alone.
Runs under floors. Victorian terraces often have drains under the ground floor. Digging under a timber floor is a major job, and it is costly. Meanwhile, relining the same section from an outside access point costs far less.
Limited access. Some homes have narrow side passages or no rear access. Basement flats may need digging below the water table. Because of this, a no-dig repair is a big advantage.
When Excavation Is Unavoidable
Relining is not a universal fix. Sometimes digging is the only option, and a liner would fail or give a poor result.
Total collapse. If the pipe has fallen in on itself, a liner has no bore to pass through, so there is nothing to line. You must dig, remove the old pipe and replace it.
Deformed pitch fibre pipe. Pitch fibre pipes turn oval or collapse over time. A round liner cannot fit an oval bore. The rough surface also stops a good bond. Digging and replacing is the standard fix.
Blockages that will not clear. Concrete, hard grease or broken pipe pieces can form a rigid blockage. If jetting cannot shift it, you must dig to remove it before any repair. A liner would still fail over such a blockage.
Very short sections at connections. A branch joining a main pipe can be too short or too awkward for a liner. A patch repair may work. If not, a small local dig is the most practical choice.
A failed previous lining. A liner that has peeled away or collapsed must come out before a new one goes in. Removing it sometimes needs a dig.
Comparing the Costs
We price relining per metre, with a minimum charge. Excavation means breaking up the surface and replacing the pipe. We then reinstate the surface. The cost depends on depth, length and surface type. Reinstatement costs more in London, because so many surfaces are paved to a high standard.
Take a 10-metre run under a tarmac drive. Digging and reinstating costs much more than relining the same section, because the surface needs full repair. Wherever relining is technically possible, the economics favour it.
Our drain repair pricing page gives a fuller breakdown by scenario.
Making the Decision
A CCTV survey is the only reliable basis for the choice. Be wary of any contractor who recommends digging before a survey. Be wary too of anyone who promises relining without one, since they are guessing.
The survey report should grade each pipe run. It should give a clear recommendation for each defect. For relining, it should state the liner size, the method (inversion or pull-in), the curing method and the warranty. For digging, it should state the depth, length, surface type and how the surface will be restored.
What London Conditions Mean for the Decision
London sits largely on London Clay. This stiff clay shrinks and swells with the seasons. Movement is greater in dry summers, particularly near mature trees. Victorian and Edwardian clay pipes move with the ground. Over a century, that movement leaves offset joints and cracks around the pipe. Our CCTV surveys record these faults all the time. The good news is that this is the damage pattern relining was designed to repair, because the pipe itself is still sound.
Digging in central and inner London also costs more than elsewhere. Many streets have quality flagstones, granite kerbs and conservation-area surfaces. Councils require owners to restore these to the original standard. Sometimes the borough picks the contractor. A trench across a Camden conservation pavement can cost more to restore than to repair. Many other services also run under London streets, including water mains, cables and gas pipes. Digging at any depth needs careful service searches and often hand-digging. All of this pushes the choice towards relining whenever the pipe is suitable.
FAQ
Can relining be used in any size of pipe?
Standard home liners suit a wide range of pipe sizes. Larger liners exist for commercial drains and sewers. The liner maker states the smallest pipe each product can fit.
How long does pipe relining last?
Manufacturers typically quote a design life of 25 to 50 years for a well-fitted resin liner. The host pipe must be sound before lining, because the liner relies on it.
Will relining affect my drainage flow?
The bore shrinks only a little, while the smooth liner cuts friction. The smooth liner usually improves flow compared with a rough clay pipe full of roots. Flow is rarely worse.
Do I need planning permission for drain repair works?
Drain repair, including relining, is not normally a planning matter. If the drain is close to a public sewer, you may need a build-over agreement from Thames Water for digging. Relining happens inside the existing pipe, so it does not trigger that rule.
Can you assess and repair a drain in London?
We can carry out a CCTV survey across Greater London. After the survey, we advise whether to reline or dig. Request a quote online via our contact form to arrange a survey.
Because every property is different, start with our guides to drain repairs & relining and pipe relining advice. We also cover drain repairs & relining in Beckenham and drain repairs & relining in Bromley, so you can see how the work runs near you.
