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Suppliers of: Shallow foundation system polystyrene raft foundations

A Complete foundation system that offers both cost savings and excellent thermal performance.

Insulslab is a complete BBA Certified and Patented foundation system, based on a type of raft foundation which comprises a series of interlocking expanded polystyrene pods, forming a substantially rigid ‘waffle’ shaped slab (waffle foundation system). Steel fibre reinforced concrete is poured over the top to form the finished foundation.

Insulslab is an innovative high quality, patented (GB2385071) foundation system that is suitable for use on a wide range of soil types for both residential houses and commercial constructions of up to four stories high.

Insulslab offers substantial benefits for the developer, architect, structural engineer and ground worker: -

  • Increased speed of construction, reduced labour costs, excavation costs and reduced waste costs.
  • Excellent thermal performance - typical U-values of around 0.10 - 0.12W/m2K, depending on P/A ratio.
  • Significant cost savings - a typical saving of 25 - 33% over traditional beam and block/raft.
  • Shallow foundation system requires minimal excavation.
  • BBA Certified and accepted by the NHBC/LABC and Premier
  • Compliance with Part L without the need for an additional layer of insulation and screed. 
  • Meets Part E (Section 5 Scotland) sound insulation requirements when used as proprietary Robust Details construction.
  • Code for Sustainable Homes & BREEAM credit scores. Green Guide Rating.
  • Perfect for brownfield sites and contaminated soils
  • Less volume of concrete required and no rebar and mesh reinforcement.
  • Health & Safety benefits with no heavy blocks to lift.

A complete specification and installation support service.

Insulslab’s specialist technical team, including engineering, U-value calculations and on-site technical support. General arrangement drawings and quantified costs can also be provided, as well as steel fibre reinforced concrete calculations from ArcelorMittal.

FOUNDATION Clayheave Protection .
FOUNDATION Construction Reinforced Concrete
FOUNDATION Contractors .
FOUNDATION Design Shallow Depth
FOUNDATION Design and Construction .
FOUNDATION Ground Movement Protection .
FOUNDATION Systems BREEAM Credit Scores .
FOUNDATION Systems Code for Sustainable Homes .
FOUNDATION Systems Contaminated Sites .
FOUNDATION Systems Contaminated Sites Gas Protection
FOUNDATION Systems Contaminated Sites Gas Protection CS3/Amber 2
FOUNDATION Systems NHBC/LABC/Premier Requirements .
FOUNDATION Systems Part L Building Regulations (Section 6 Scotland)
FOUNDATION Systems Shallow Depth Minimal Dig Alternative to Traditional Piled/Vibro Foundations
FOUNDATION Systems Shallow Depth Minimal Dig Alternative to Traditional Raft Foundations
FOUNDATION Systems Shallow Depth Minimal Dig Insulating Expanded Polystyrene Pods EPS
FOUNDATION Systems Shallow Depth Minimal Dig Interlocking Insulation Pods
FOUNDATION Systems Shallow Depth Minimal Dig NHBC LABC Approved Code for Sustainable Homes
FOUNDATION Systems Shallow Depth Minimal Dig Steel Fibre Reinforced Concrete SFRC
FOUNDATION Systems Shallow Depth Minimal Dig Trenchless / No Trench Foundations
FOUNDATION Systems Waffle Systems Rafts .
FOUNDATIONS Contaminated Land .
FOUNDATIONS Insulated Ground Floor Systems .
IN-SITU CONCRETE Floors and Foundations Steel Fibre Reinforced AGREMENT CERTIFICATE HOLDERS
RAFTS Foundation Polystyrene Pods Insulating Moulds
ARCELORMITTAL (SUPPLIER) Steel Fibres for Concrete
ARCELORMITTAL INSULSLAB Steel Fibre Reinforced Concrete


November 2013


Having been targeted to achieve an additional 25 percent carbon reduction on top of the Building Regulations, Countryside Properties turned to Insulslab, a super insulated and fully integrated foundation system, to increase energy efficiency at Saxon Park – a new affordable homes development in Warrington.

At the time of plot registration, the development was required to meet Level 3 of the Code for Sustainable Homes, with specific employer requirements mandating that it must also significantly improve on the current Building Regulations for carbon reduction.

As a system that integrates insulation into its design using lightweight expanded polystyrene (EPS) pods, Insulslab achieves very low U-values, typically 0.10 – 0.12W/m2K (depending on P/A ratio). With steel fibre reinforced concrete (SFRC) poured on top of the pods, Insulslab SFRC delivers the foundation up to ground floor level, contributing to the overall thermal performance of the building envelope.

Used in conjunction with a standard open panel timber frame system at Saxon Park, Insulslab offered improved airtightness as the two systems integrated well to virtually eradicate thermal bridging at the junctions.

As the site was also a former steelworks, there were additional challenges with regards to ground preparation and foundation construction. Requiring minimal ground excavation and no trenches, Insulslab SFRC provided an efficient foundation technique that could also easily accommodate sloping parts of the site. This included a stepped construction of 2.2 metres in one area, which would not have been possible with a traditional raft.

Andrew Fox, Countryside Properties’ technical standards manager, comments:

“Given the challenges facing us on the site and the stringent energy efficiency criteria set by the client, we needed a solution that would deliver the required performance without significantly impacting on build cost. The flexibility of Insulslab SFRC and its proven thermal insulation credentials made it the best specification for Saxon Park, as the higher levels of insulation in the floor made it easier for us to meet the required performance without having to increase floor depth or insulation in the wall cavities.”

Although Countryside Properties originally looked to Insulslab SFRC as a solution to help achieve the specified carbon reduction, the system also proved a key factor in increasing on-site efficiency. While groundworkers Caldwell Construction originally anticipated one week per plot based on traditional raft techniques, using Insulslab SFRC the team was able to construct a plot foundation in just three days.

Andrew continues:

“We have been extremely impressed with the speed of installation because in spite of a late start on-site, we were able to make the time back by using timber frame in conjunction with Insulslab – two very efficient and modern methods of construction.”

The simplicity of system installation is facilitated by the components being easy to manage. For example, the EPS pods minimise manual handling as they are sufficiently light for a one-man lift, while the use of SFRC removes the need for traditional steel reinforcement, which can often prove difficult to manoeuvre on-site.

Mark Gray, technical manager, Insulslab SFRC, concludes:

“Insulslab is specified for three reasons – time saving, cost saving and enhanced thermal performance. The installation programme at Saxon Park demonstrates how the system can simultaneously deliver on all three counts, even under the most challenging of site conditions or timescales.”

Insulslab Approved as Robust Specification for Separating Walls

November 2013

Robust Details Limited has approved the use of Insulslab insulated raft foundation system for separating walls and is now named in Appendix A2 as being an accepted base for cavity masonry separating walls incorporating the Icopal-MONARFLOOR BRIDGESTOP system. As before, where a raft foundation is indicated within the relevant detail, Insulslab SFRC can also be used as a base for steel and timber frame walls.

Manufactured from interlocking expanded polystyrene (EPS) pods with steel fibre reinforced concrete (SFRC) poured on top, Insulslab delivers the foundation up to ground floor level and removes the need for a topping screed. In doing so the system interfaces directly with separating walls, making it eligible for approval under the Robust Details scheme.

Andrew Orriss, Insulslab, comments: “Insulslab is now widely adopted by national housebuilders as a preferred foundation technique. Offering time and cost savings on-site it has proven its worth as an efficient construction method, but it also affords a wide range of thermal and sustainable benefits. By being approved for use with separating masonry wall constructions we expect adoption of Insulslab SFRC to extend much further with developers who favour the Robust Details route.”

Insulslab has been specifically approved for the following:

E-WM-1, E-WM-8, E-WM-17, E-WM-2, E-WM-11, E-WM-18, E-WM-3, E-WM-12, E-WM-20, E-WM-4, E-WM-14, E-WM-21, E-WM-5, E-WM-16, E-WM-22

The addition of Insulslab as an approved foundation system with the specified separating walls is due for publication in the next update of the Robust Details Limited Handbook.

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