How and where to use guide
Rigid PIR Insulation 1200 x 2400 x 120mm
Typical applications and suitability
This 120mm thickness suits mid-range thermal requirements in building fabric upgrades. The boards are suitable for use in floors (where the 175 kPa compressive strength supports domestic and light commercial loading), cavity wall insulation, timber frame construction, and pitched or flat roof applications. The standard board dimensions make them practical for both new build installations and retrofit work where existing structural openings and joist spacings align with the 1200mm width. They are not suitable for applications requiring higher compressive strength or where thermal performance exceeding 0.022 W/mK is specified.
- Floors: suitable for domestic and light commercial loading conditions
- Walls: cavity fill and timber frame applications
- Roofs: pitched and flat roof thermal upgrades
- New build and retrofit projects where mid-range U-values are acceptable
Installation and handling on site
The 1200 x 2400mm board format is designed for manual handling by two operatives on most sites. Store boards flat and dry before installation to maintain performance. When installing, ensure boards are cut cleanly using a fine-toothed saw or hot wire cutter to achieve tight butt joints and minimise thermal bridging. In floor applications, lay boards directly onto prepared substrates and secure according to structural engineer recommendations; in wall cavities, support boards adequately to prevent sagging; in roof applications, ensure boards are fully supported by rafters or joists and ventilation requirements are maintained where specified. Always follow the relevant building control guidance and the manufacturer's installation instructions supplied with your specific brand.
- Store flat and dry before installation
- Cut cleanly with fine-toothed saw or hot wire cutter for tight joints
- Ensure full support on floors, walls and roofs to prevent deflection
- Maintain ventilation paths in roof applications as required by building regulations
- Follow manufacturer and building control installation guidance
Performance and limitations
The 0.022 W/mK thermal conductivity provides consistent insulation performance suitable for mid-range thermal upgrades; thicker boards or lower conductivity materials may be required for higher performance targets. The 175 kPa compressive strength is adequate for typical domestic floor loading and standard wall/roof applications but should be verified for heavy-duty or commercial loading scenarios. PIR foam is combustible and must be protected by appropriate fire barriers or cavity trays in accordance with building regulations. The boards are moisture-resistant but not waterproof; they must not be exposed to prolonged water contact or used in permanently wet environments.
- Thermal conductivity 0.022 W/mK: suitable for mid-range upgrades only
- Compressive strength 175 kPa: verify suitability for heavy or commercial loading
- Combustible material: requires fire protection barriers per building regulations
- Moisture-resistant but not waterproof: protect from prolonged water exposure
Maintenance and on-site tips
Once installed and protected, rigid PIR boards require no routine maintenance. During storage and installation, protect boards from direct sunlight, rain and physical damage to prevent degradation and maintain thermal performance. If boards are cut on site, collect and dispose of offcuts responsibly; small offcuts can be retained for filling gaps, but ensure all voids are sealed to prevent air leakage and maintain thermal continuity. Do not apply incompatible adhesives or sealants that may degrade the foam; use only products recommended by the board manufacturer. On completion, ensure all exposed edges are protected or covered to prevent mechanical damage and UV exposure.
- Protect from sunlight, rain and physical damage during storage and installation
- Seal all gaps and voids to maintain thermal continuity
- Use only manufacturer-approved adhesives and sealants
- Protect exposed edges from mechanical damage and UV exposure after installation