Partial Fill Cavity Boards

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Partial Fill Cavity Wall Insulation Boards Partial fill cavity wall insulation is designed to fit within the cavity of masonry walls while maintaining a residual gap between the insulation and the outer leaf. This air space allows for moisture drainage , helping to protect internal structures from wind-driven rain and damp penetration—especially in exposed locations. Partial fill systems are a trusted solution in new build housing , extensions , and commercial walls where both insulation and moisture management are priorities. At Insulation UK , we stock a range of high-performance rigid PIR and phenolic cavity boards from industry-leading brands like Kingspan and Recticel , all BBA certified and suitable for use in traditional brick-and-block construction . Key Partial Fill Cavity Products: Kingspan Thermawall TW50 is a rigid PIR insulation board with foil facings on both sides. It offers a thermal conductivity of 0.022 W/m·K , fits easily between wall ties, and maintains a 50mm residual cavity for moisture control—ideal for standard masonry wall construction. Kingspan Kooltherm K108 is a high-performance phenolic cavity board faced with low-emissivity foil. With a thermal conductivity as low as 0.018 W/m·K , it's perfect for applications where space is limited but exceptional thermal performance is required. It’s designed for use in partial fill systems, particularly where a slim wall build-up is beneficial. Recticel Eurowall Partial Fill is a PIR cavity insulation board with rebated edges for minimal thermal bridging and tight jointing. With a thermal conductivity of 0.022 W/m·K , it’s ideal for partial fill installations in new masonry cavity walls, offering a balance of moisture protection and efficient insulation performance. Ideal For: Brick-and-block cavity walls in new builds and extensions Projects requiring a residual air cavity for moisture drainage Walls exposed to wind-driven rain zones Installations needing a balance of thermal efficiency and building