A Practical Guide to Pipe Relining Repairs

A damaged drain does not always mean excavating a driveway, lifting a commercial floor or disrupting a busy site. This guide to pipe relining repairs explains when a no-dig repair is a practical option, how the work is carried out and when a replacement pipe is still the right decision.

For homeowners, property managers and contractors across Greater London, the priority is normally the same: stop the defect from causing blockages, leaks, odours or structural damage, with as little disruption as possible. Relining can often achieve that, but only after the pipe has been properly inspected and prepared.

What pipe relining repairs involve

Pipe relining is a trenchless method of repairing the inside of an existing drain or sewer pipe. A flexible liner, saturated with a specialist resin, is installed within the damaged section. Once positioned, the liner is expanded against the host pipe and cured to form a new, durable pipe within it.

The finished liner seals cracks, open joints, small fractures and areas affected by root ingress. It also creates a smooth internal surface that can improve flow through a pipe that has become rough, worn or locally damaged over time.

This is not a temporary patch. When the pipe condition and installation are suitable, a cured-in-place liner provides a long-term structural repair without the excavation associated with conventional replacement. It is particularly useful where drains run beneath patios, landscaped areas, internal floors, car parks or roads.

When relining is a suitable repair

A CCTV drainage survey is the starting point. It shows the pipe’s route, diameter, material and condition, while identifying the exact location and nature of any defects. Guesswork is not a sound basis for a repair decision, especially where a fault may affect a shared drainage run or a commercial operation.

Relining is commonly suitable for pipes with longitudinal cracks, leaking joints, minor displacement, root intrusion and corrosion. It can also be effective where repeated blockages are being caused by a rough or deteriorated internal surface rather than a simple one-off obstruction.

The practical benefit depends on access. If engineers can reach the section through existing manholes, rodding points or other suitable entry points, the work may be completed with little or no excavation. This can reduce reinstatement costs and minimise downtime for occupied properties, retail premises, offices and managed sites.

A liner may be installed as a full-length repair or as a local patch repair. A patch liner treats one defined defect, such as a cracked joint, while a full liner rehabilitates a longer pipe run. The most suitable approach depends on the survey findings, the number of defects and the expected future use of the drainage system.

When excavation may be the better option

Relining cannot correct every problem. A pipe that has fully collapsed, has severe displacement, has lost its line or gradient, or contains extensive voids may need excavation and replacement. The same applies where the pipe is badly misshapen and there is insufficient internal space for a liner to be installed correctly.

There is also a modest reduction in the internal diameter after relining. In most standard drainage applications this is not significant, but it must be considered in already undersized or poorly designed pipework. A competent survey and repair assessment should explain these limitations before work begins.

The pipe relining repair process

A reliable repair is mainly about preparation. Installing a liner into a pipe that is still blocked, coated with scale or affected by active root growth risks a poor result. The process should therefore begin with cleaning and inspection, not simply inserting a liner.

First, the drain is cleaned using the appropriate method, often high-pressure water jetting. This removes debris, grease, scale, silt and roots so the pipe wall can be assessed and the liner can bond and sit correctly. In difficult cases, specialist cutting equipment may be needed to remove roots or solid obstructions.

Engineers then carry out a CCTV survey to confirm the measurements and check that relining remains suitable. The liner is cut to the required length, impregnated with resin and introduced into the pipe. Depending on the system and site conditions, it may be pulled into place or inverted using air or water pressure.

Once it is correctly positioned, the liner is expanded and cured. Curing methods vary and may involve ambient conditions, hot water, steam or ultraviolet light. The chosen method should match the liner system, pipe size and working environment.

After curing, any necessary branch connections are reopened using remote cutting equipment. A final CCTV inspection confirms that the liner is continuous, properly seated and free from installation defects. For commercial and construction clients, retaining this survey evidence can be useful for maintenance records, handover information and future asset planning.

Signs your drains may need more than unblocking

A single blocked sink or toilet can be caused by a local obstruction. However, recurring problems often point to an underlying defect further along the line. Slow drainage, repeated blockages in the same area, persistent foul odours, damp ground near the drain route and visible root growth around inspection chambers all justify further investigation.

Other warning signs include unexplained subsidence, wastewater backing up through low-level fittings, or drains that clear temporarily after jetting but block again soon afterwards. Cleaning restores flow, but it cannot seal a fractured pipe or repair a failed joint. A CCTV survey establishes whether the problem is maintenance-related or structural.

For landlords, facilities teams and managing agents, early investigation is usually less disruptive than waiting for a complete failure. A developing defect can affect several occupiers, create hygiene concerns and lead to emergency call-outs at inconvenient times.

Cost, disruption and other practical considerations

The cost of pipe relining repairs varies with the pipe diameter, length, access points, depth, number of branches and the condition found during the survey. A local repair can be more economical than relining an entire run, while a longer liner may offer better value where defects are widespread.

It is sensible to compare the full scope of each option rather than the repair price alone. Excavation may involve breaking out surfaces, exposing the pipe, removing spoil, installing replacement pipework, testing and reinstating paving, flooring or landscaping. Relining can avoid much of this work, but it is not automatically the least expensive choice in every situation.

For a domestic property, access through an inspection chamber may make the work relatively straightforward. At a commercial site, the drainage route could pass beneath loading areas, plant rooms or public spaces, so safe working arrangements and operational timing become part of the plan. Two-person crews, clear site controls and accurate survey information help keep the work safe and organised.

Responsibility should also be checked before repairs are authorised. Some drains serve a single property, while others are shared or connect to public sewers. The location of the defect and the ownership of the pipe can affect who is responsible for arranging and paying for the work.

Choosing a contractor for pipe relining

The right contractor should diagnose before recommending a repair. Ask whether the quotation is based on current CCTV evidence, whether cleaning is included, what length and type of liner is proposed, and whether a post-repair survey will be provided. Clear answers are a good indication that the scope has been properly assessed.

Experience matters because drainage defects are rarely identical. The engineer needs to distinguish between a pipe that can be rehabilitated, a pipe requiring a local patch and one that needs replacement. They should also be able to manage associated work such as drain cleaning, root removal, surveys and emergency drainage support without passing responsibility between multiple providers.

Burch Drainage Ltd provides inspection-led drainage repairs across Greater London, helping domestic and commercial clients choose a repair method that suits the actual condition of their pipework rather than a one-size-fits-all solution.

If recurring drainage problems are affecting your property or site, arrange a CCTV survey before the damage becomes harder to manage. A clear view inside the pipe gives you the evidence needed to plan the right repair, protect the surrounding area and keep the drainage system working as it should.