Fixing and buying guide

Who this product is for

EUROWALL + PIR boards are suitable for builders and experienced DIY installers undertaking cavity wall insulation in new build or renovation projects. They work equally well in timber-framed construction and masonry cavity wall systems where a full fill insulation approach is required. This product is ideal if you need rigid foam insulation that combines thermal performance with straightforward installation.

Compatibility and cavity width

These 90mm boards are engineered to fit standard cavity widths commonly found in UK construction. Before ordering, measure your cavity width to confirm 90mm thickness is appropriate for your wall build-up. The boards are compatible with both timber-framed and masonry cavity construction methods. Check that your cavity is clear of obstructions, mortar droppings, and debris before installation begins.

• Suitable for timber-framed cavity walls
• Suitable for masonry cavity walls
• 90mm thickness fits standard cavity widths
• Full fill cavity system — boards should fill the cavity completely

Board size and pack contents

Each board measures 1200 × 460mm, which allows you to cover wall areas efficiently with minimal cutting and waste. Calculate your total wall area and divide by the board area (0.552 square metres per board) to determine the number of boards required. We stock boards from leading manufacturers including Ecotherm, IKO, Mannok, Recticel, and Unilin, subject to availability. Check the specific brand and availability when ordering.

• Board dimensions: 1200 × 460mm
• Board area: 0.552 square metres
• Thickness: 90mm rigid PIR foam
• Edge profile: Tongue and groove for tight joints

Pre-installation checks and fixing

Before installation, inspect the cavity to ensure it is clean, dry, and free from debris, mortar droppings, and obstructions. The tongue and groove edges must be fully engaged to minimise thermal bridging and air leakage — ensure boards are pushed together firmly during installation. Boards should be supported by the cavity wall structure; follow the specific fixing guidance provided by the board manufacturer, as requirements may vary between brands. Do not compress the foam excessively during installation, as this will reduce thermal performance.

• Clear cavity of debris, mortar droppings, and obstructions
• Ensure cavity is dry before installation
• Engage tongue and groove edges fully between boards
• Follow manufacturer's fixing and support guidance
• Do not compress the foam core during installation