Celotex XR4150 150mm PIR Insulation is highly versatile and can be used for many floor, wall, roof, and other applications. Celotex PIR Insulation was voted the best thermal insulation product of the UK. 150mm Celotex Insulation boards are made from a rigid polyisocyanurate (PIR) foam with aluminium foil faces on both sides. These 150mm Celotex Insulation Boards are one of the most efficient insulation product available. Their thermal conductivity is just 0.022 W/mK, beating most other products on the market. 150mm Celotex XR4150 PIR Insulation is made using a combination of eco-friendly blowing agents that have been proven to have low global warming potential and zero ozone depletion potential (ODP). Celotex XR4150 is certified by the BBA to be used for roof, wall, and floor applications, provided it is stored and used in accordance with the certificate.