Filcor 20 - Expanded Polystyrene (EPS) Structural Fill Material

Filcor 20 EPS (Expanded Polystyrene) is used as a lightweight structural fill alternative to more traditional fill materials or as a lightweight void former in structural concrete. It can be used up to 800mm thick of 25kN/m3 concrete above it.

Filcor Expanded Polystyrene (EPS) is a lightweight structural fill and void‑forming material used as an alternative to traditional granular fill or as a void former within reinforced concrete. It is manufactured in customisable sheet or block sizes and can be cut or profiled to suit complex shapes, falls, steps or landscaping features. Filcor is widely used in hard and soft landscaping, podium slabs, swimming pools, infill works, and off‑site construction, where its low weight, high insulation value and predictable compressive performance offer significant installation and design advantages.

Filcor is available in a range of grades, each offering a different compressive strength and maximum allowable concrete depth, ensuring the correct specification for pedestrian, vehicular or structural loading conditions. 

Note: Filcor EPS sheet can be ordered to the required thickness, from 25mm to 1200mm.

CHARACTERISTICS

• Lightweight structural fill - ideal where reducing load on the sub‑base or structure is essential.
• Range of compressive strengths - grades tailored to specific loading and concrete depths.
• Custom sizes and profiling - can be supplied as sheets, blocks or profiled shapes.
  
• High insulation value - provides thermal performance in addition to structural function.
  
• Easy to cut and install - workable with a fine‑toothed saw or hot‑wire cutter.
  
• Water‑resistant and durable - unaffected by moisture and offers long design life.

APPLICATIONS

• Lightweight structural fill for hard and soft landscaping
• Void formers in concrete
• Podium slabs
• Swimming pool construction and infill
• Steps, ramps and shaped profiles
• Off‑site prefabricated elements

INSTALLATION

• Filcor must sit on a firm, even surface to prevent point‑loading and settlement.
  • Remove loose material, debris and organic matter
  • Compact the sub‑base to the engineer’s specification
  • Ensure the surface is level to within acceptable tolerances
  • Lay a blinding layer (sand or fine aggregate) if required for smoothing

• Install Separation Layer (If Required), which prevents chemical interaction and allows Filcor to move independently of the substrate.
  • Lay a polythene sheet or geotextile over the prepared base
  • Overlap joints by 150–300 mm
  • Tape or weight edges to prevent movement during installation

• Filcor is installed in staggered layers to maximise stability and load distribution.
  • Lay the first layer tightly with minimal gaps
  • Stagger joints like brickwork to avoid continuous vertical seams
  • Ensure blocks are fully supported across their entire underside
  • Trim pieces with a fine‑toothed saw or hot‑wire cutter as needed
• Build Up in Multiple Layers (If Required) - Deep fills require perpendicular layering to maintain structural integrity.
  • For depths over 1200 mm, rotate each new layer 90° to the one below
  • Maintain tight joints between blocks
  • Fill any small voids with off‑cuts to avoid concrete intrusion
• Install Top Separation Layer - A membrane prevents wet concrete from penetrating joints and ensures even load transfer.
  • Lay polythene or geotextile directly over the top Filcor layer
  • Overlap and tape joints to prevent concrete ingress
  • Ensure the membrane is smooth and wrinkle‑free

• Concrete must be placed evenly to avoid localised compression of the EPS.
  • Pour concrete gently and uniformly across the surface
  • Do not drop concrete from excessive height
  • Avoid concentrated loads from pumps, wheelbarrows or workers
  • Finish to the required depth for the Filcor grade used
• Once installed, Filcor requires minimal maintenance but must be protected before final finishes.
  • Inspect for membrane breaches or exposed EPS
  • Ensure edges are protected from UV and mechanical damage
  • Proceed with subsequent construction layers once concrete has cured

CERTIFICATION

• Filcor complies with both BS EN 13163:2008 and BS EN 14933:2007