EPS Insulation Boards UK – High-Performance Expanded Polystyrene for EWI

Renders World supplies a professional-grade range of EPS insulation boards UK — engineered for External Wall Insulation systems that meet the demands of modern UK building regulations. As part of our complete EWI systems, our expanded polystyrene insulation UK range offers the thermal performance, dimensional stability, and system compatibility required by professional installers, contractors, and specifiers across the country.

Product Overview — What This Category Covers

This category encompasses graphite EPS boards UK and standard expanded polystyrene boards for external wall insulation applications. EPS (Expanded Polystyrene) is a lightweight, rigid insulation manufactured to EN 13163 standard, supplied in thicknesses from 10mm to 200mm to suit reveal insulation, standard solid wall upgrades, and high-performance Passive House retrofits. Our premium graphite-enhanced boards incorporate high-purity graphite particles that reflect radiant heat within the cellular structure, delivering a superior thermal conductivity of 0.031–0.032 W/mK — making them the leading choice for eps thermal insulation UK projects requiring slender wall profiles alongside maximum energy efficiency.

Key Benefits & Technical Advantages

• Superior thermal conductivity: Graphite-enhanced boards achieve λ 0.031 W/mK, providing up to 20% better thermal performance than standard white EPS at equivalent thickness.
• Future Homes Standard compliance: Available in thicknesses up to 200mm, enabling projects to achieve the mandatory 0.18 W/m²K wall U-value under the 2026 regulatory framework.
• EN 13163 certification: Every board is manufactured to this European standard, ensuring consistent compressive strength (70 kPa), dimensional accuracy, and BBA/ETA system compatibility.
• Biological resistance: EPS is naturally resistant to fungi, mould, and bacteria, ensuring no biological degradation within the wall cavity over its service life.
• Lightweight and fast to install: Low density reduces handling fatigue on-site and allows rapid board application, improving programme efficiency on large-scale retrofits.
• Fire performance: Self-extinguishing Euroclass E classification, suitable for residential buildings under 11 metres in height in compliance with Approved Document B.

Technical Specifications / Selection Guide

Use the reference table below to select the correct board thickness for your target R-value and application. All values apply to graphite EPS at λ 0.031 W/mK.

Application & System Compatibility

Our eps board solid wall insulation UK range is fully compatible with BBA/ETA certified EWI systems and suitable for a wide variety of substrates, including solid brickwork, blockwork, timber frame, and SFS (steel frame systems). Boards are adhesive-ready for use with polymer-modified basecoat adhesives and CT84 adhesive foam, and accept mechanical fixings at a minimum density of 6–8 fixings per m² to resist wind uplift. The range is optimised for use under thin-coat silicone and mineral renders for a crack-resistant, breathable facade finish.

For a deeper technical comparison of insulation materials and guidance on meeting the 2026 regulatory targets, read our graphite EPS vs mineral wool 2026 facade guide.

Is This Right for Your Project?

• Choose EPS insulation boards if: You are working on low-rise residential or commercial properties under 11 metres, require cost-effective high-performance thermal insulation, need a lightweight system for fast installation, or are specifying for Future Homes Standard 0.18 W/m²K wall targets.
• Consider alternatives if: Your project involves buildings over 11 metres or high-risk occupied buildings requiring non-combustible A1-rated insulation — in this case, explore our mineral wool range within the broader EWI systems collection.

Frequently Asked Questions

What thickness of graphite EPS is required to comply with the Future Homes Standard 2026?

To achieve the mandatory wall U-value of 0.18 W/m²K under the Future Homes Standard, graphite EPS boards with λ 0.031 W/mK typically require a thickness of 150mm to 160mm, depending on the thermal performance of the existing wall substrate. For full regulatory guidance and U-value calculation methodology, refer to our article on Future Homes Standard 2026 compliance in the UK.

Are EPS insulation boards compatible with all EWI adhesives?

Yes. Our boards are adhesive-ready and compatible with polymer-modified cementitious adhesives (such as Atlas Hoter U and Ceresit ZU) as well as CT84 adhesive foam. The choice of adhesive will depend on substrate porosity, board thickness, and system certification requirements. Always ensure the adhesive is specified within a BBA or ETA certified system.

Can EPS boards be used for floor insulation beneath screed?

Yes, provided the boards meet the load-bearing requirements of the application. Our EPS boards carry a compressive strength of 70 kPa, which is suitable for residential floor insulation beneath floating screed where point loads do not exceed this specification. For higher load applications, consult the relevant EN 13163 product data sheet.

What is the difference between graphite EPS and standard white EPS?

Graphite EPS incorporates high-purity graphite particles that reflect and absorb radiant heat within the foam matrix, reducing thermal conductivity from approximately 0.038 W/mK (standard white EPS) to 0.031–0.032 W/mK. In practical terms, this means you can achieve equivalent thermal resistance using a board 20–30mm thinner, reducing wall thickness, window reveal depth, and material weight on-site.