Special Products

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SHIMPAC® CHAMBER Collars are quick and easy to install, without the need for specialist tools or equipment and is compatible with fast setting mortar. The product range comes in various thicknesses, allowing the contractor to build up the area beneath the frame to achieve the correct level. Designed specifically to secure the chamber top and provide a platform to bed and level any ironwork to exactly the right height and angle.

SHIMPAC planks and collars are a combination of compressed cement (70%) and treated wood fibres (15%).

Compressive Strength
39-49 N/mm2 (Independent site and laboratory testing)

Dimensional Stability
1.5% expansion when soaked overnight in water (bucket test)

8.6% after 24 hours total immersion

Will not rot – suitable for use as permanent shuttering

Fire Rating
Non combustible

Mortar Compatibility
Can be installed using fast setting mortar

On Site Cutting

  • Tungsten tipped saw (where necessary)
  • Stihl saw / disc cutter
  • Planks up to 24mm thickness can be scored and snapped to length

Health and Safety
Download our COSHH data sheet


  • Custom carriageway and footpath ironwork support e.g.
  • Manhole frames and covers specialist sizing
  • Bespoke Gully gratings sizing
  • One off specialist projects
  • Unit 8a,
  • Lower Road Trading Estate,
  • Ledbury,
  • Hereford, HR8 2DJ
  • United Kingdom

T: +44(0)1531 633 771

E: enquiries@shimpac.com

Standard Sizes


Standard Thickness