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How AJS Environmental repaired a leaking manhole chamber and restored hydraulic performance using specialist sealing and coating systems.
Serving Essex, London, Kent & Hertfordshire with specialist manhole sealing, infiltration repair & flow restoration.
When manholes begin to leak, erode or allow groundwater infiltration, it creates serious issues across the drainage system — including reduced flow efficiency, accelerated pipework deterioration, foul odours and increased site flooding risk.
AJS Environmental provides professional manhole sealing services designed to stop infiltration, protect benching and restore the performance of your drains. In many cases, manhole sealing is carried out as part of a wider Find & Fix drainage service, where faults are diagnosed and repaired with minimal disruption.
This case study shows how our engineers repaired a failing manhole chamber and improved system flow using a multi-stage sealing and coating process.
Integrated with Find & Fix Drainage & UV Lining
Manhole sealing is a critical component of AJS Environmental’s Find & Fix drainage service.
Infiltration and benching failure at chamber level often indicate wider system issues, which is why
our sealing works are commonly combined with CCTV drain surveys, robotic cutting, and UV drain lining
to deliver a complete, long-term repair solution.
Why Choose AJS Environmental for Manhole Sealing?
- Stops groundwater infiltration entering foul or storm systems
- Restores damaged benching and prevents further erosion
- Improves hydraulic flow through pipe connections
- Long-lasting waterproof coatings built for harsh environments
- Ideal for commercial estates, retail parks, industrial sites and domestic properties
What Is Manhole Sealing?
Manhole sealing is a targeted no-dig repair method used to correct internal chamber failures such as cracks, open benching, infiltration points and eroded flow channels.
Over time, manholes deteriorate due to:
- Water infiltration through cracks or defective joints
- Eroded benching caused by turbulence and repeated surcharging
- Root ingress and structural movement
- Chemical attack from foul drainage
- General ageing across drainage assets
AJS Environmental uses specialist sealing compounds and high-build coatings designed for wastewater structures, creating long-term waterproof protection and improved flow characteristics. Where required, condition is confirmed first with a CCTV drainage survey.
Why Manhole Sealing Is Essential Before Drain Lining
Even when pipes are structurally sound, leaking or eroded manhole chambers can undermine the entire drainage system.
Groundwater infiltration at chamber level increases hydraulic load, accelerates pipe deterioration and can compromise
the performance of downstream lining installations.
By sealing infiltration points, rebuilding benching and applying high-build waterproof coatings, AJS Environmental ensures that subsequent UV lining or patch repairs
are protected and perform as intended for the long term.
Stage 1 – Stopping Infiltration & Rebuilding Benching
The first stage involved identifying active infiltration and areas of structural weakness. Water was entering through eroded benching and open voids around the pipe entry.
Our engineers:
- Applied fast-set sealing products to stop active leaks
- Filled voids and rebuilt benching to restore structural strength
- Smoothed and reshaped the flow channel to improve hydraulics
- Stabilised fragile surfaces to prepare for long-term coating
Leak Elimination
Using rapid-set hydraulic mortars, we seal infiltration even in wet conditions — ideal for live foul systems where flow cannot be fully isolated.
Hydraulic & Structural Improvement
Rebuilding and reshaping benching improves stability and directs flow efficiently towards the outgoing pipe, reducing turbulence and erosion.
Stage 2 – Final Coating to Improve Flow & Prevent Future Damage
After repairs were completed and leaks eliminated, we applied a high-build waterproof coating engineered for manhole environments.
Benefits of the final coating include:
- Creates a smooth, seamless surface that improves flow efficiency
- Resists erosion, chemicals and high moisture exposure
- Protects the chamber structure from further deterioration
- Provides a long-lasting waterproof barrier around pipe connections
Serving Clients Across the Region
- Essex – Basildon, Chelmsford, Southend, Colchester & surrounding towns
- London – Inner & Greater London commercial drainage networks
- Kent – Dartford, Medway, Maidstone & surrounding areas
- Hertfordshire – St Albans, Watford, Hemel Hempstead & nearby towns
Manhole Sealing: Helpful Links
Suitable for Highways, Commercial & Public Sector Assets
Manhole sealing is frequently specified on highways, retail parks, industrial estates, schools, housing association assets and public drainage networks.
Our engineers carry out sealing works in live environments, including wet conditions and out-of-hours access windows, with minimal disruption.
These repairs are often delivered as part of night-time or restricted-access programmes alongside patch lining and UV drain rehabilitation.
Need Manhole Sealing or Infiltration Repair?
Our engineers deliver long-lasting manhole sealing, infiltration repairs and flow restoration across commercial, domestic and public-sector sites.
Download Our Manhole Sealing PDF Guide
Frequently Asked Questions
Why do manholes start leaking?
Cracks, eroded benching, pipe joint failure and groundwater pressure can all contribute to infiltration inside manholes.
Do you need to isolate flow before sealing?
No — our sealing compounds can be applied in wet conditions, including live drainage systems.
How long does manhole sealing take?
Many chambers can be sealed and coated in a single visit, depending on access, condition and live flow levels.
How long does the coating last?
High-build coatings are designed for long-term durability, chemical resistance and waterproof structural protection.
Is manhole sealing a permanent repair?
Yes. When correctly specified and applied, modern manhole sealing systems provide long-term protection
against infiltration, erosion and chemical attack, and are commonly used alongside structural lining
solutions for full system rehabilitation.
Related Services & Resources
- Find & Fix Drainage Services
- CCTV Drainage Surveys
- UV No-Dig Drain Lining
- Patch Lining Repairs
- Robotic Cutting
