Jablite is the UK's largest producer of EPS products for insulation and civil engineering applications



Jablite Claymaster (Clay Heave Protection) is a BBA certified product that provides protection against clay heave.

Shrinkable clays are soils containing a large proportion of mineral particles of less than 0.002mm in diameter. This produces an extremely cohesive soil type when wet, but shrinks to a crumbly, crazed structure when dry. The expansion and contraction process during wet and dry periods is known as ‘clay heave’. This can cause severe problems with foundations.

Jablite Claymaster works by surrounding the pile cap with a layer of low density, compressible, expanded polystyrene, reducing pressure on the ground beams as the surrounding clay expands and contracts.

Key Benefits
  • BBA (British Board of Agrément) accredited, certificate 90/2543
  • A permanent solution to clay heave problems
  • Easy to install
  • Negligible compression during concrete casting
  • No need for specialist trades or equipment
  • Resistant to moisture
  • Lightweight
  • Durable
  • A+ rated in the BRE Green Guide to Specification

Need more help?

BBA Certificates and other supporting documents can be found in Technical Resources

Technical Resources
Downloads & Specifications

BBA Certificates and other supporting documents can be found in Technical Resources

Technical Resources
Technical information
Product specification

Jablite Claymaster insulation is supplied:

Board sizes 2400 x 1200mm
Standard thicknesses 50, 75, 100, 150 and 200mm

NHBC Requirements

Thickness of Claymaster to comply with NHBC requirements


Soil heave potential Underside of beam Against side of foundations & beams
NHBC void dimension Equivalent Claymaster NHBC void dimension Equivalent Claymaster
High 150mm 250mm 35mm 75mm
Medium 100mm 175mm 25mm 50mm
Low 50mm 100mm 0mm 0mm


Download the Jablite Claymaster Technical Datasheet




+Is Jablite accredited to ISO 9001?
Yes, all Jablite sites are accredited to BS EN ISO 9001 Quality Management System.
+Is Jablite packaging environmentally friendly?
Jablite is continuously striving to reduce packaging on its products. Products are wrapped in film as and when necessary to protect them during transport and storage on site. Ongoing efforts have been made to minimise the thickness of film used to reduce the packaging further. Pallets are used when requested by customers, but wherever possible recyclable EPS 'skids' are used.
+Which thicknesses are available to order in Claymaster?
There are standard thicknesses which are 50, 75, 100, 150 and 200mm. However, other thicknesses may be available to order.