
90mm Celotex Thermaclass Cavity Wall 21 Full Fill Insulation Board T&G 1190mm x 450mm (3.21m2/Pack)
by Celotex
Prices updated 12 Apr 2026
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Product Description
Celotex Thermaclass Cavity Wall 21 Full Fill Insulation Board with a 90mm thickness and 1190mm × 450mm dimensions. High-performance rigid polyisocyanurate (PIR) insulation board designed for use in full fill masonry cavity wall applications. Manufactured with a low emissivity foil facing, it delivers exceptional thermal conductivity of 0.021 W/mK, helping achieve low U-values while reducing overall wall thickness requirements. The tongue and groove edge profile provides a tight, secure fit, minimising air gaps and thermal bridging. The board can be installed as a full fill solution or with a residual cavity of up to 10mm to accommodate mortar squeeze and simplify installation. Lightweight, rigid, and easy to handle, the board fits standard wall tie spacing, supporting fast, efficient on-site fitting. The 90mm thickness provides high insulation performance for standard-depth wall cavities in residential and commercial construction.


