Seating Rings / Adjusting Units
Elite Precast manufactures high-quality precast concrete seating rings and adjusting units designed for precise manhole and chamber level adjustment within drainage systems.
Engineered for strength, durability and dimensional accuracy, our concrete adjusting rings provide a reliable solution for achieving correct cover and frame levels in highways, commercial and residential developments across the UK.
Designed to sit on top of the manhole cover slab, seating rings eliminated laying engineering bricks, reducing the reliance on brick availability, cost increases and the weakening of vertical joints, which reduces the likelihood of infiltration.
What is Seating Rings / Adjusting Units?
Concrete seating rings, also known as adjusting rings or raising pieces, are precast concrete components used to adjust the height of manholes, inspection chambers and access covers.
They are installed between the chamber structure and the cover slab or frame to:
Achieve finished surface level
Ensure correct alignment with road or ground level
Maintain structural integrity
Provide long-term load distribution
Why Choose Elite Precast
With decades of precast expertise, in-house engineering support and a proven delivery record on projects of every scale, Elite Precast is the partner specifiers trust. We pair robust, repeatable manufacturing with the flexibility to engineer bespoke solutions when a standard product will not do.
Key Features & Benefits
Manufactured from high-strength precast concrete
Multiple height options available
Precision-cast for accurate installation
Designed for heavy-duty load classifications
Suitable for adoptable drainage systems
Our multi-part adjusting units offer the advantage of light weight sections enabling one man to handle the units and comply with manual handling requirements.
Why Choose Seating Rings / Adjusting Units?
Precast concrete offers superior performance compared to alternative materials:
High compressive strength
Excellent load-bearing capacity
Longer service life
Consistent dimensional accuracy
Resistant to ground movement and traffic loads
Reduced floatation
Decreased likelihood of infiltration
Fast and easy installation
Less manual handling of bricks
More predictable installation process
Reduced risk of poor workmanship
Resistant to frost damage, sulphate attack and mortar degradation
Lower maintenance costs
All units are manufactured under strict ISO 9001 quality controls to meet UK construction standards.
We understand the importance of programme timelines and installation efficiency and how ensuring your drainage components arrive ready for immediate use is important.
Finish & Appearance
Appearance of a hairline crack in a seating ring or gully cover does not signify failure or a cause for rejection.
It is the responsibility of the customer to check that the proposed cover and frame flange is fully supported by the chosen adjusting system as flange sizes may vary.
Compliance & Technical Support
Elite Precast seating rings and adjusting units are manufactured in accordance with BS EN 1917:2002 and BS 5911-3:2010.
Our team works closely with contractors and engineers to ensure:
Structural suitability
Correct load classification
Dimensional accuracy
Safe handling and installation
Technical drawings and specifications are available upon request.
Seating Rings / Adjusting Units and Section 38 Agreements
Section 38 (Highways Act 1980) is the term for the legal agreement that allows a highway authority to 'adopt' a road (meaning it will be maintained by the highways authority at the public's expense) which has been constructed by a private developer for 5 or more dwellings.
The developer must be able to prove that the road has been constructed in accordance with standards set out by the highways authority to enable the highways authority to be able to 'adopt' it under a Section 38 legal agreement.
In the case of concrete frame adjusting/seating rings, units manufactured to BS EN 1917 and BS 5911-3 are shown in both Manual of Contract Documents for Highways Works – Volume 3 – Highway Construction Details – F-Series and in Sewers for Adoption and are therefore deemed to be accepted for use in highway construction.
Gallery
Full specifications
Important downloads
- DownloadGuidance for Adjusting Units and Seating RingsPDF850 KB
Frequently Asked Questions
What are concrete adjusting rings used for?
Concrete adjusting rings are used to raise or fine-tune the height of manholes and drainage chambers so that covers align correctly with finished ground or road level.
Are seating rings suitable for highways?
Yes. Our precast concrete seating rings are designed to withstand heavy traffic loads and are suitable for highway and infrastructure applications when installed correctly.
What are seating rings made from?
Our seating rings are manufactured from high-strength precast concrete, ensuring durability, structural performance and long service life.
Are your adjusting units compliant with UK standards?
Yes. Our products are manufactured in accordance with BS EN 1917 and BS 5911-3 and meet UK construction standards.
Why are seating rings used instead of brickwork?
Concrete seating rings are used instead of brickwork mainly for strength, speed, compliance, and long-term performance, especially in adoptable highway and drainage works. They provide greater strength, faster installation, and reduce the risk of joint failure, settlement and water infiltration.
What are notched seating rings?
Notched Seating Rings is a type of precast concrete seating ring, made by Elite Precast Concrete, that includes a cast-in recess (Notch) to accommodate a toe hole or finger slot to make entering the manhole system easier.
What are eccentric and corbel units used for?
They create offset openings that improve access for fire operatives and meet emergency access requirements.
What are Lothian Seating Slabs?
They are precast concrete slabs designed to meet Scottish Water specifications for adjusting manhole covers and frames.
Are seating rings suitable for adoptable roads (S38)?
Yes. They are manufactured to BS EN 1917 and BS 5911-3 and are suitable for use in Section 38 adoptable highway schemes.
Are they suitable for S104 sewer adoption?
Yes. They are widely used in Section 104 sewer adoption schemes and comply with industry guidance.
Can seating rings withstand heavy traffic?
Yes. They are designed to handle high loads, including heavy vehicles and continuous traffic.
Do seating rings reduce maintenance requirements?
Yes. Their durability and structural integrity reduce the need for ongoing repairs compared to traditional brickwork.
Can seating rings be used across multiple plots?
Yes. Their consistent dimensions make them ideal for repeat use across large developments.
Do seating rings help speed up construction programmes?
Yes. Their ready-to-install design reduces labour time and helps maintain project timelines.
UK Manufacturing & Nationwide Delivery
Every product is manufactured in the UK to recognised quality standards and delivered nationwide on a fleet built for site access. The result is shorter lead times, full control over quality, and the confidence of working with a British manufacturer.
Need Seating Rings / Adjusting Units on a project?
Request a quote or talk to our technical team.