Safe-R Under Floor SR/UF is a superior performance rigid phenolic insulation with low emissivity aluminium facings both sides and has a thermal conductivity as low as 0.020 W/mK, delivering excellent U-values in floors. The floor in any building is an area of considerable downward heat loss when not properly insulated. SR/UF will significantly improve the U-value of new and existing floors. SR/UF is lightweight, easy to install and combines high compressive strength with low thermal conductivity, providing a high performance solution for floor insulation.