How and where to use guide
QL Kraft PIR Insulation 2400mm x 1200mm x 40mm + 12.5mm Insulated Plasterboard
Rafter and Roof Applications
This product is ideally suited for installation between and under roof rafters to significantly reduce heat loss through the roof structure and eliminate thermal bridging caused by the timber rafters themselves. The 40mm PIR thickness provides substantial thermal resistance whilst the integrated plasterboard creates a finished ceiling surface in one application. Installation involves securing the board directly to the underside of the rafters, with the kraft paper facing towards the roof space to provide vapour control. Ensure adequate ventilation above the insulation layer to prevent moisture accumulation. The plasterboard face provides an immediate decorative finish that requires only joint taping and finishing.
- Fix perpendicular to rafters using appropriate mechanical fixings or adhesive suitable for rafter applications
- Ensure the kraft paper facing is positioned towards the roof void for correct vapour control
- Maintain clear ventilation pathways above the insulation to prevent condensation
- Stagger board joints to avoid weak points in the structure
- Seal all joints and penetrations with appropriate tape or sealant
Dry-Lining and Internal Wall Applications
The product performs excellently in dry-lining applications on internal walls, where it can be fixed using either dot-and-dab adhesive or mechanical fixings. The kraft paper facing provides additional rigidity and vapour control properties, whilst the bonded plasterboard eliminates the need for separate board installation. This method is particularly effective for upgrading thermal performance on external walls or creating insulated partition walls. The integrated plasterboard finish means walls are ready for decoration after joint finishing.
- Apply dot-and-dab adhesive in five-point pattern or use mechanical fixings as per building regulations
- Ensure substrate is clean, dry and reasonably level before installation
- Kraft facing should be positioned facing the room interior for vapour control
- Maintain minimum 150mm clearance from ground level to prevent moisture ingress
- Use appropriate joint tape and compound to finish plasterboard seams
Key Installation Considerations
The board dimensions of 2400mm x 1200mm allow efficient coverage with minimal waste. The 40mm insulation thickness combined with 12.5mm plasterboard creates a total board depth of 52.5mm, which should be accounted for in design and detailing. The fibre-free PIR core means no irritant particles during handling, making it safer for on-site operatives. Always check local building regulations for thermal performance requirements and ensure the kraft facing is correctly oriented to provide vapour control on the warm side of the insulation.
- Handle boards carefully to avoid damage to plasterboard face during transport and installation
- Protect kraft facing from moisture during storage and before installation
- Account for the 52.5mm total thickness in all design details and junction specifications
- Ensure all fixings penetrate through plasterboard into solid substrate with adequate grip length
- Do not use in areas subject to high moisture or wet conditions without additional protection
Limitations and Maintenance
This product is designed for internal use in dry conditions and should not be exposed to prolonged moisture or used in wet rooms without additional protective measures. The kraft paper facing provides vapour control but is not a complete vapour barrier, so adequate ventilation must be maintained in rafter applications. Once installed and finished, the plasterboard surface requires standard maintenance as for any internal plasterboard finish. Do not use mechanical fixings that penetrate the kraft facing without sealing the penetration points to maintain vapour control integrity.
- Not suitable for external exposure or wet room applications without additional protection
- Protect from moisture during storage and installation
- Seal all fixings and penetrations to maintain vapour control layer integrity
- Maintain adequate ventilation in rafter applications to prevent condensation