Cellcore HX S

Cellcore HX S is designed for use beneath reinforced concrete floor slabs to protect against the potential effects of ground heave. The product consists of a cellular construction of Expanded Polystyrene which has been designed, moulded and tested to tight tolerances to achieve the specified performance characteristics. 


  • Reduces the upward force transmitted to the structure from ground heave
  • Wide range of profiles and grades to suit most applications
  • BBA certified
  • Meets the NHBC’s Technical Standards
  • BRE Global Verified Environmental Product Declaration (EPD)
  • Moulded production for enhanced and consistent performance
  • Available with integral Filcor insulation, permanent formwork for ground beams or passive gas venting
  • Patented Product Technology

The standard range of products are available in a variety of depths and grades to suit most commonly encountered combinations of soil heave potential and concrete depth. Variations of the product are also available for use under pile caps and ground beams or alternatively where integral insulation, permanent formwork or passive gas venting is required.


The Cellcore HX S range is designed to protect reinforced concrete floor slabs from the upward forces associated with the effects of ground heave.


Firstly the depth of the Cellcore HX S panel should be determined by the heave potential of the soil, as detailed in table one below:

Table One: 

Results of Soil Analysis NHBC Category

Predicted Ground Movement or BRE/NHBC requirement

Depth of Cellcore HX required to achieve 'Equivalent Void'
Plasticity Index Shrinkage Category Void Dimension (mm) HX S (mm)
10-20 Low 50 90
20-40 Medium 100 160
40-60* High 150 225

Table Two:

Cellcore HX Grade * Safe Load (kN/m2) Fail Load (kN/m2) Maximum Concrete Depth ** (mm)
7/10 7 10 220
9/13 9 13 300
13/18 13 18 460
18/24 18 24 660
24/32 24 32 900
32/42 32 42 1220

* For easy identification the panel labels are coloured as shown.

** Based on the Eurocode and a live load allowance of 1.5kN/m2.

For concrete thicknesses between 1220mm and 2000mm, further grades of Cellcore are available. For further advice please contact the Cordek Technical Team on 01403 799600.


Data Sheets

Product Issue Date Version Size Download
Cellcore HX Data Sheet 12/2022 5 1.2 MB

MSDS Data Sheets

Product Issue Date Version Size Download
Expanded Polystyrene MSDS 06/2017 5 137.3 KB

Certification, Approval & Guidance

Product Issue Date Version Size Download
EPD Certificate - Cellcore HXS 03/2023 1 852.9 KB
BBA Certificate - Cellcore HX 09/2021 3 526.4 KB


Product Issue Date Version Size Download
Construction Solutions 01/2020 2 6.6 MB
Ground Heave Solutions 08/2017 1 1,014.7 KB

Installation Guides

Product Issue Date Version Size Download
Cellcore Installation Guide 09/2019 2 798.4 KB

NBS Clauses

Our NBS Clauses are hosted on the external website - view NBS Clauses

BIM Library

Please select the BIM file in the format you require.

Name IFC Size IFC Download Revit Size Revit Download
Cellcore HX S 28.7 KB 948.0 KB

Not sure which product meets your requirements?

Contact a Technical Advisor now

Case Study

Emmanuel Church

Cordek was asked to provide heave protection measures to protect the church's new floor from possible future ground movement.

Find your nearest Technical Advisor

For international enquiries please contact Peter Blanchard

For enquiries in the Manchester or Liverpool
areas please contact James Provan

Or contact Cordek Head Office