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675x675mm Central Access Concrete Adjusting Unit - 2 piece.
  • 675x675mm Central Access Concrete Adjusting Unit - 2 piece.
  • 675x675mm Central Access Concrete Adjusting Unit Dimensions.
  • 675x675mm Central Access Concrete Adjusting Unit on a Cover Slab.

675 x 675mm Central Access Concrete Adjusting Unit (2 piece)

Up to 10 working days
Up to 10 working days
Large Item
From £229.31
£229.31 - £687.91
From £191.09 ex. VAT

This product is only available in certain pack sizes. To purchase individual items please contact us for availability.

Product Details


Product Type: Adjusting Unit/Seating Ring
Model Type: Two Piece
Access Size: 675x675mm
Access Position: Central
External Dimensions: 935x935mm
Unit Weight: 65kg
Available Pack Sizes: 5's, 10's, and 15's only

This 675x675mm Two Piece Cover Frame Adjusting Unit is a reinforced, 65mm deep seating ring which can be used in place of engineering bricks to adjust ductile or cast iron covers and frames to the required level.

Being a two piece model means that each half weighs less than 33kg for easier maneuvering on site.

Product Features at a Glance:

  • Quicker and easier to install than brickwork
  • Designed as seating for manhole cover
  • Replaces the need for engineering bricks on-site
  • No requirement for bricklayers due to ease of installation.
  • The 65mm thickness is similar to brickwork
  • Fewer joints which reduce the likelihood of infiltration
  • Reduced risk of onsite damage and pilferage
  • All concrete manhole units can be ordered from one source
  • Kitemarked to BS EN 1917 / BS EN 5911-3

Concrete Manhole Adjusting Units (also known as risers or seating slabs/rings) are used to "adjust" cast/ductile iron covers to their required level. These units can be stacked on top of each other to fit between where a cover slab is and where the iron cover needs to be, thus eliminating the need to lay engineering brick.

They are a practical and economical alternative to engineering brick, providing both height adjustment and robust seating for an iron cover and frame assembly at a fraction of the install time. The use of adjusting units is specified in ‘Sewers for Adoption’.

Customer Notice: Seating rings are supplied in the following pack sizes and cannot be split: 600mm & 675mm square standard and 2 part = 15's, 10's or 5's, 750mm square and 750mm x 600mm = 10's only, 1200mm x 675mm and 600mm Sq Eccentric = 10's or 5's.

 Key Features of CPM Concrete Products:

  • Quality - Precast concrete drainage products are manufactured in accordance with the relevant BS EN 1916/7, BS EN 5911 and CE marked where applicable. Goods are certified by Quality Assessment under the Kitemark Scheme and ISO 9001:2015.
  • Sustainability - Concrete pipeline systems are one of the most sustainable options available, they are manufactured from responsibly sourced materials, and can be made using recycled aggregates and cement replacements.
  • Proven Strength - They have a proven life of over 120 years, in normal groundwater conditions, are not weakened by fire or moisture and do not lose their shape. They are resistant to DC4 and impacts such as jetting, so blockages can be cleared easily.
  • Installed Cost Savings - Precast concrete pipes are rigid structural elements that do not always require a full granular surround, saving time in bedding and compaction. Excavated material can be reused and imported granular material can be reduced to a minimum.
  • Durability - Due to the inherent strength and durability of the Marshalls CPM precast concrete products, they are highly abrasion and corrosion resistant and don't lose strength over time.
  • Design Flexibility - Precast concrete drainage products can be used for a number of purposes, including sewerage and sustainable urban drainage systems (SuDS) applications such as stormwater attenuation and storage.
  • Water Tightness - Concrete pipes and manholes are designed to be watertight and are tested to pressure levels equivalent to a 5 metre head of water.
  • Fire Resistant - Concrete is naturally fire resistant. 

Please Note: All dimensions and weights are approximate. Customers should ensure that lifting equipment has sufficient capacity to allow for variations. All images shown are used for illustration purposes only and may differ from the actual product supplied.

Disclaimer: It is the customer’s responsibility to check that the proposed cover and frame flange is fully supported by the chosen adjusting system as flange sizes vary between manufacturers.

Up to 10 working days
Product Type:
Adjustment Unit
Marshalls CPM
Nominal Size: