Claymaster Insulation Sheet 2400 x 1200mm – 50mm

Claymaster Insulation Sheet 2400 x 1200mm – 50mm is a BBA-certified, low-density expanded polystyrene (EPS) compressible-fill board manufactured by Jablite (BEWI), purpose-built to protect foundations from the damaging effects of clay heave. Widely specified by structural engineers, groundworkers, and self-builders across the UK, it provides a permanent, maintenance-free solution wherever shrinkable clay soils threaten foundation stability.

Key Features and Specifications

• Dimensions: 2400mm × 1200mm × 50mm (8ft × 4ft nominal)
• Coverage: 2.88m² per sheet
• Material: Low-density compressible expanded polystyrene (EPS)
• Colour: Pink — for easy on-site identification and differentiation from standard EPS boards
• BBA Certified: Assessed by the British Board of Agrément under Regulation A2; Certificate No. 90/2543
• NHBC Approved: Complies with NHBC Standards Chapters 4.2, 4.3, and 4.4
• BRE Green Guide Rating: A+ — suitable for sustainable and BREEAM-assessed projects
• Moisture resistance: Does not degrade in high-moisture or below-ground conditions
• Freeze-thaw resistance: Maintains performance through repeated wet/dry and freeze-thaw cycles
• Fire: Installed below ground in concrete foundations; when correctly specified per BS 6203, presents no undue fire hazard
• Weight: Approximately 1.6 kg per sheet — lightweight and easy to handle without specialist equipment
• Available thicknesses: 50mm, 75mm, 100mm, 150mm, 200mm (300mm made to order)

Applications

• Clay heave protection around pile caps and piled ground beam foundations
• Sides and base of deep trench fill foundations in shrinkable clay soils
• Permanent shuttering for cast in-situ reinforced concrete substructures
• Reducing lateral pressure on ground beams in new-build housing and extensions
• Foundation protection on sites classified as high or very high clay shrinkage risk

Why Choose This Product

Claymaster is the UK’s leading specified clay heave protection board, trusted on new-build and extension projects nationwide. Its BBA and NHBC approvals satisfy building control and warranty requirements without additional testing. Negligible compression during concrete casting means no loss of performance at the critical pour stage. No specialist trades or tools are needed — sheets cut cleanly with a handsaw and install quickly, reducing labour costs on site. The A+ BRE Green Guide rating supports sustainable specification and BREEAM credits.

Delivery in and Around London

We deliver the Claymaster Insulation Sheet 2400 x 1200mm – 50mm to all London boroughs, including Croydon, Lewisham, Southwark, Camden, and Hackney, as well as Greater London areas such as Enfield, Bexley, Redbridge, and Barnet. We also supply regularly into the surrounding counties of Kent, Essex, Surrey, and Hertfordshire. Trade quantities and pallet orders are welcome — contact us for volume pricing. Same-day or next-working-day despatch is available on stocked items; please enquire for your specific postcode.