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Insulating Concrete Formwork “building shell” systems

Insulating concrete formwork (ICF), also known as Permanently Insulated Formwork (PIF), is the family name for highly insulated concrete walling systems which are growing rapidly in popularity as the Government push toward ‘zero carbon’ homes .

ICF systems are however equally suitable for any building type as demonstrated in North America and Canada where they are widely used for basements and above ground structure in both domestic and commercial buildings.

ICF consists of two skins of Expanded polystyrene (EPS) insulation either side of a defined void in which RMX concrete is pumped. The EPS skins are separated using a grid of plastic ties which lock together without any intermediate bedding materials to provide the formwork. The formwork stays in place to give the wall its required thermal insulation which can reach down to levels as low as 0.11 W/m2degk.

The wall construction is extremely airtight and the building shell can be built to meet the German ‘Passivhaus’ standard  required (depending upon final doors and window specification).

Using the compressive strength properties of the concrete core, precast concrete upper floors can easily be incorporated into the design and supported by the ICF walling system. With no linear cold bridging conditions occurring, due to the external skin of EPS insulation positioned to the outside face of the floor slab section, the ICF shell provides an ideal thermal envelope resulting in vastly reduced energy bills and a minimal internal space heating requirement.

Design, supply and installation service:

Aggregate Industries' Charcon Integrated Solutions team provide a design, supply and installation package service for clients using a total envelope “fabric first” approach to the construction, using:-

  • Insulated raft foundation
  • ICF walling
  • Precast hollowcore upper floors
  • Precast stairs and lift shafts
  • Insulated panel roofing systems

The ICF wall panels can be manufactured as off-site produced panels, usually storey height x length of defined wall (max approx 9m long). These pre-made panels are then transported to site with their door and window openings already formed and are easily lifted into place and braced into position prior to the concrete being pumped into the wall section.

Ready-mixed concrete options:

Aggregate Industries has developed a number of sustainable ready-mixed concretes for ICF applications which can be delivered through our own concrete teams. The “ICF-Crete” mixes are available in a variety of strengths and densities with the inclusion of cement replacements and can include recycled and secondary aggregates where required. 

We were the first construction materials company worldwide to be certificated under the BRE (Building Research Establishment) Global BES6001 Framework for Responsible Sourcing for the production of its construction materials. This certification gives credits towards all BREEAM schemes including the Code for Sustainable Homes.

All of our ready-mixed concrete is manufactured under the QSRMC quality assurance scheme and complies with EN206 BS8500. ICF- Crete has been specifically designed to be used as an ICF pump grade ready-mixed concrete and comprises of an S3 slump classification together with a small (10mm) aggregate size. Each mix design can also be tailored to fulfill the specification of the client, whether it contains a required percentage of replacement and/or secondary materials.

View ICF-Crete technical information

Flooring options for ICF systems
Aggregate Industries also produces various flooring types to suit ICF systems. 

Concrete options for ground floors include:

  • Ready-mixed concrete slab
  • Raft foundations
  • Piled foundations and ground beams

Concrete options for upper floors include:

  • Precast beam and block floors
  • Precast beam and ready-mixed concrete cast on polystyrene formwork
  • Precast hollowcore slabs
  • Precast solid slabs



1  The Concrete Centre ICF system brochures and Design Guide
2 Insulated Concrete Formwork Association UK
3 Insulated Concrete Formwork Association North

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