Celotex CW4000 provides a simple solution for partial fill cavity walls. High performance insulation featuring low emissivity foil facings CW4000 offers enhanced thermal performance in cavity air spaces compared to typical PIR solutions. These enhanced values deliver thinner solutions to meet popular target U-values. Celotex CW4000 is supported by BBA certification achieves an A+ rating when compared to the BRE Green Guide. Always install Celotex CW4000 in accordance with the instructions supplied by Celotex.