How and where to use guide

Installation and cavity preparation

Before installation, inspect the cavity for debris, mortar droppings and moisture. Clear the cavity base thoroughly as any obstruction will compromise board seating and thermal performance. Measure cavity width to confirm suitability for the 90mm board plus residual cavity allowance. Boards should be installed horizontally, starting from the base of the cavity and working upwards. Push boards firmly into place, ensuring tongue and groove edges interlock fully to create continuous joints with no gaps. The aluminium facing acts as a vapour control layer, so ensure boards are installed with facing towards the inner leaf. Do not compress or force boards as this damages the foam and reduces thermal efficiency.

• Clear cavity of all debris and mortar droppings before starting
• Install boards horizontally from base upwards
• Ensure tongue and groove edges are fully interlocked
• Maintain 10mm residual cavity gap behind the board for moisture management
• Do not compress boards during installation

Suitable applications and limitations

This product is designed for masonry cavity walls in new build construction and retrofit insulation projects. It is suitable for standard cavity widths where 90mm insulation plus 10mm residual cavity can be accommodated. The board is not suitable for cavities narrower than 100mm total width or for applications where the cavity cannot be kept clear of moisture. Do not use in exposed cavities without proper cavity trays and weep holes to manage water ingress. The product is intended for masonry-to-masonry cavities; specialist advice should be sought for other cavity configurations or where structural movement is anticipated.

• New build and retrofit masonry cavity wall applications
• Standard cavity widths accommodating 90mm board plus 10mm residual cavity
• Not suitable for cavities narrower than 100mm total width
• Requires functioning cavity trays and weep holes for moisture management
• Not for use in cavities subject to water ingress or poor drainage

Thermal and moisture performance

The rigid polyisocyanurate foam core delivers high thermal resistance, whilst the multi-layer aluminium foil facing on both sides provides additional thermal reflection and acts as a vapour control layer. The 10mm residual cavity behind the board is essential for moisture management and must not be eliminated. This air gap allows any moisture that enters the cavity to migrate and evaporate, protecting the masonry and inner leaf from dampness. The aluminium facing prevents moisture vapour from the inner leaf penetrating the foam, maintaining long-term performance. Do not seal or block the residual cavity as this will trap moisture and cause deterioration.

• Aluminium foil facing provides thermal reflection and vapour control
• Residual 10mm cavity essential for moisture evaporation and management
• Do not seal or block the cavity behind the board
• CFC, HCFC and HFC free blowing agents ensure environmental compliance

On-site handling and storage

Store boards flat and dry on site, protected from weather and direct sunlight. Stack boards carefully to avoid crushing the foam core or damaging the aluminium facing. Do not expose boards to prolonged moisture or allow water to pool on stacks. Handle boards with care during transport and installation to prevent impact damage to edges and faces. Damaged boards with crushed foam or torn facing should not be installed as this compromises thermal performance and vapour control. Ensure adequate site access for board delivery and positioning to minimise double handling. Plan installation sequence to avoid boards remaining exposed in the cavity for extended periods.