Drain Lining (No-Dig Repairs) – Plain-English Guide

What is drain lining?

Drain lining—often called CIPP (Cured-In-Place Pipe)—is a no-dig technique that forms a new watertight inner surface inside an existing pipe. A resin-impregnated liner is inserted and expanded against the host pipe, then cured to create a smooth, structural sleeve that seals cracks, joints, and minor defects.

When lining is (and isn't) suitable

• Suitable: intact but defective pipes; repeated leaks; multiple faulty joints.
• Borderline: significant ovality or steps—needs careful survey; sometimes partial excavation first.
• Not suitable: collapsed or heavily deformed sections, severe offsets, or where diameter is sharply restricted.

A recent CCTV drain survey is the best way to confirm suitability.

Patch vs full-length lining

• Patch (local) liner: short section (e.g., 0.5–1m) to repair one defect. Cost-effective when the rest of the run is sound.
• Full-length liner: rehabilitates a long run to treat several joints/cracks at once; fewer future joints left unsealed.

Choice depends on defect locations, access, bends, and cost/benefit. Sometimes a mix—one full liner plus a short patch—gives the best result.

How the lining process works

1. Survey & design: confirm defects, dimensions, bends, and reinstatement points.
2. Cleaning/prep: jetting/descaling and debris removal so the liner bonds well.
3. Liner insertion: inverted or winched into place via access chambers.
4. Inflation: air/water bladder expands the liner against the host pipe.
5. Curing: ambient, hot water, steam, or UV (depending on system) to harden the resin.
6. Reinstatements: lateral connections reopened using robotic cutters.
7. Final survey: post-lining CCTV to evidence the result and seal quality.

Benefits of lining

• No excavation in most cases (less disruption)
• Seals multiple joints and hairline cracks in one go
• Smoother bore improves flow and reduces snagging
• Rapid return to service compared with dig-and-replace

Limitations & risks

• Won't fix a collapsed pipe or severe deformation
• Requires good cleaning and access; heavy scale/roots must be removed first
• Complex bends, junctions, and diameter changes need careful design
• Poor prep or curing can create wrinkles/folds that trap debris

Where collapse or major misalignment exists, targeted excavation or section replacement may be the right first step.

Costs & what affects them (ballpark)

• Length & diameter of the run (more resin, more curing time)
• Access (number/depth of chambers, indoor vs outdoor)
• Pre-works (jetting, descaling, root cutting)
• Bends, junctions, and reinstatements count
• Curing method (UV/steam setups can affect pricing)

Short patches are generally cheaper per job; full liners may be better value across multiple defects.

Lifespan & aftercare

Quality CIPP liners are designed for long service life when correctly specified and installed. Aftercare is simple: avoid wipes/fats, consider periodic checks if you previously had root ingress, and keep records (pre/post CCTV, drawings, and curing notes) for future reference or insurance.

Compliance & documentation (plain-English)

• Keep the pre- and post-CCTV reports and stills
• Record the liner spec, diameter, length, resin/cure method
• Note any reinstated laterals and locations
• Retain plans/sketches for future works or claims

FAQs

Will lining reduce the pipe diameter?

Slightly, but the smoother bore often improves hydraulic performance overall. Correctly sized liners maintain adequate capacity.

Can you line over severe offsets?

Minor offsets can be bridged; severe steps often require excavation or spot repair first, then lining.

Does lining stop tree roots?

Yes—by sealing joints and cracks. Roots must be cut out first; the liner then prevents re-entry through those points.

Is lining suitable for all pipe materials?

Commonly used in clay, uPVC, and concrete. A CCTV survey confirms host suitability.