GUIDE 05
DRAIN LINING
EXPLAINED
Everything you need to know about drain lining, when it's used, how it works and how long it lasts.
Drain lining is a modern, trenchless repair method that restores damaged underground drains from the inside without the need for extensive excavation.
Used in the right circumstances, it can provide a long-lasting, cost-effective solution while minimising disruption to your property.
IN THIS GUIDE
01 Quick Answer
02 What is Drain Lining?
03 Types of Drain Lining
04 How Does Drain Lining Work?
05 When is Drain Lining Used?
06 When Isn't Drain Lining Suitable?
07 Why We Don't Recommend Drain Lining for Every Defect
08 Benefits of Drain Lining
09 Drain Lining vs Excavation
10 Why Preparation is Critical
11 How Long Does Drain Lining Last?
12 Aftercare & Maintenance
13 Why Choose Drainsmart?
14 Need Advice About Drain Lining?
15 Frequently Asked Questions
16 Related Guides & Articles
01 Quick Answer
Drain lining repairs damaged pipes from the inside using specialist resin-impregnated liners, creating a new pipe within the existing one.
When suitable, it is faster, less disruptive and often more cost-effective than excavation, with many installations lasting 50 years or more.
02 What is Drain Lining?
Drain lining is a trenchless repair technique that restores the structural integrity of damaged underground pipes without excavation.
A resin-impregnated liner is inserted into the existing pipe before being expanded and cured in place.
Once hardened, the liner forms a seamless new pipe within the original pipe, sealing cracks, defective joints and minor structural defects.
03 Types of Drain Lining
We use a range of drain lining techniques depending on the condition of the drainage system, the location of the defect and the most appropriate long-term repair solution.
Structural Soft Felt Lining
Our most commonly used drain lining method.
A resin-impregnated felt liner is installed within the existing pipe to create a strong, seamless new pipe without the need for excavation.
Ideal for:
-
General structural repairs
-
Cracks and fractures
-
Leaking joints
-
Root penetration
-
Longer pipe runs
-
Multiple defects within the same section of pipe
Structural Patch Lining
Designed for isolated defects where the remainder of the pipe is in good condition.
Rather than lining the entire pipe, a short structural patch is installed only where the damage has occurred.
Suitable for:
-
Short cracks
-
Localised joint failures
-
Small sections of damaged pipe
-
Isolated root penetration
Inversion Lining
Used where continuous structural lining is required over longer distances.
The liner is inverted into the pipe using air pressure before being cured to form a durable new pipe within the existing one.
Ideal for:
-
Longer pipe runs
-
Multiple structural defects
-
Continuous rehabilitation of ageing drainage systems
-
Situations where excavation would be particularly disruptive
Reinstating Branch Connections
Where a structural liner passes across existing branch connections, these are reinstated following installation using our specialist Dancutter robotic cutting system.
The Dancutter is guided remotely through the newly lined pipe and precisely cuts open each branch connection, restoring flow while maintaining the integrity of the structural liner.
This technique allows us to:
-
Install a continuous structural liner through the main drain.
-
Reinstate lateral connections accurately.
-
Minimise excavation around junctions.
-
Maintain the long-term performance of the lining installation.
-
Every branch connection is confirmed following reinstatement as part of our post-installation CCTV Camera Condition Inspection.
Vertical Pipe Lining
Drain lining isn't limited to underground pipework.
Where suitable, specialist lining techniques can also be used to rehabilitate vertical drainage stacks and rainwater downpipes, reducing the need for disruptive replacement works.
Ideal for:
-
Rainwater downpipes
-
Soil and vent pipes
-
Vertical drainage stacks
-
Multi-storey residential and commercial buildings
-
Pipework concealed within walls or service risers
04 How Does Drain Lining Work?
Our installation process typically follows these steps:
1. CCTV Camera Condition Inspection
2. High-pressure drain cleaning
3. Preparation of the liner
4. Installation into the existing pipe
5. Controlled curing process
6. Final CCTV inspection and quality checks
Each installation is carefully designed for the specific drainage system.
05 When is Drain Lining Used?
Drain lining is commonly recommended for:
Cracked pipes
Fractured drains
Leaking joints
Root penetration
Minor pipe collapses
Corrosion
Structural deterioration
Longer sections with multiple defects
Situations where excavation would be disruptive
The pipe must generally remain in the correct alignment for lining to be suitable.
06 When Isn't Drain Lining Suitable?
Drain lining isn't always the best solution.
Excavation may be more appropriate where:
X
Pipes have fully collapsed
X
Significant sections of pipe are missing
X
Pipes have major deformation
X
There is severe ground movement
X
Access for lining equipment isn't possible
X
Pipe replacement provides the better long-term solution
Every drainage system is assessed individually before recommendations are made.
07 Why We Don't Recommend Drain Lining for Every Defect
Drain lining is one of the most effective modern drainage repair techniques, but it isn't the right solution for every situation.
Our approach is to recommend the repair method that provides the best long-term outcome—not simply the one that's least disruptive.
Some drainage defects are better suited to localised patch repairs, particularly where the damage is confined to a small section of otherwise sound pipework.
In other situations, traditional excavation and replacement may provide the most appropriate solution, especially where the pipe has collapsed, suffered significant deformation or reached the end of its service life.
Every recommendation is based on a detailed assessment of:
-
The CCTV Camera Condition Inspection findings
-
The structural condition of the pipe
-
The extent and location of the defect
-
Accessibility
-
The expected long-term performance of the repair
-
Overall value for the property owner
Where drain lining is the most appropriate solution, we'll explain why. Equally, if another repair method is likely to provide a better long-term result, we'll recommend that instead.
Independent Recommendations You Can Trust
At Drainsmart, we don't believe in applying the same solution to every drainage problem. Our recommendations are based on evidence, experience and what's genuinely best for your drainage system.
08 Benefits of Drain Lining
Drain lining offers several advantages over traditional excavation.
✓
Minimal Disruption
No extensive digging in most situations.
✓
Faster Installation
Many projects are completed within a single day.
✓
Environmentally Friendly
Less waste, less excavation and reduced disruption.
✓
Cost Effective
Lower reinstatement costs than excavation.
✓
Long Lasting
Many installations provide a service life of 50 years or more.
09 Drain Lining vs Excavation
Drain lining is often the preferred option where the existing pipe remains structurally suitable.
Drain Lining
Minimal excavation
Faster installation
Lower reinstatement costs
Less disruption
Ideal where access is restricted
Excavation
Extensive excavation
Longer programme
Higher reinstatement costs
Greater disruption
Required where lining isn't suitable
10 Why Preparation is Critical
A successful drain lining installation begins long before the liner is inserted into the pipe.
One of the biggest factors influencing the long-term performance of a drain liner is the quality of the preparation beforehand.
Before any lining work is carried out, we carefully prepare the drainage system to ensure the liner can bond correctly and provide a durable repair.
Preparation may include:
High-Pressure Water Jetting
Specialist high-pressure water jetting removes grease, silt, loose debris and other deposits that could prevent the liner from bonding properly to the existing pipe.
Mechanical Milling
Where hard deposits, concrete intrusion, or previous repair materials are present, robotic milling equipment may be used to restore the pipe to a suitable condition before lining.
Root Removal
Tree roots are removed using specialist cutting equipment before lining is installed. Simply lining over active roots can affect the quality and longevity of the repair.
Cleaning Internal Deposits
Scale, corrosion products and other build-up are removed wherever possible to create a clean internal surface.
Confirming Pipe Suitability
Before proceeding, we confirm that the existing pipe is structurally suitable for lining. If the pipe has collapsed or is too severely deformed, another repair method may provide a better long-term solution.
Final CCTV Inspection
Immediately before installation, a final CCTV Camera Condition Inspection confirms that the drainage system has been properly prepared and is ready for lining.
Preparation Makes the Difference
A drain liner is only as good as the preparation that comes before it. Thorough cleaning, careful assessment and attention to detail help maximise the lifespan of the repair and reduce the likelihood of future problems.
11 How Long Does Drain Lining Last?
A professionally installed drain liner can last 50 years or more.
Its lifespan depends on several factors including:
-
Condition of the original pipe
-
Type of lining installed
-
Quality of installation
-
Ongoing maintenance
-
How the drainage system is used
We use high-quality materials and proven installation techniques designed to maximise long-term performance.
12 Aftercare & Maintenance
To help your lined drains last as long as possible:
-
Avoid flushing wipes, fats and oils
-
Arrange periodic CCTV inspections where recommended
-
Keep gullies and inspection chambers clear
-
Address drainage issues promptly
-
Use the drainage system responsibly
Simple maintenance helps protect your investment.
13 Why Choose Drainsmart?
Drain lining is only as good as the assessment and installation behind it.
At Drainsmart, we've been inspecting and repairing underground drainage systems for over 20 years, delivering trenchless drainage solutions across London and the South East.
Our engineers are accredited by both DrainSafe and the National Association of Drainage Contractors (NADC), giving you confidence that every repair is completed to recognised industry standards.
Our credentials include:
-
DrainSafe Accredited Contractor
-
National Association of Drainage Contractors (NADC) Accredited
-
Over 20 years' drainage experience
-
Fully insured engineers
-
15-year guarantee on qualifying lining workmanship and materials
-
Honest advice and the right repair for your drainage system
14 Need Advice About Drain Lining?
Not sure which repair method is right for your drainage system?
Our experienced team will assess the condition of your drains, explain your options clearly and recommend the most appropriate long-term solution.
Request a quotation today or call us on 02086633699
15 Frequently Asked Questions
Our Drain Lining FAQ includes:
-
Is drain lining permanent?
-
How long does it last?
-
Is excavation ever required?
-
How much does drain lining cost?
-
Is my drain suitable for lining?
-
Does drain lining reduce the pipe diameter?