Since 1990 there has been a requirement by Building Regulations to insulate ground floors to reduce energy consumption. With ever-increasing pressure to reduce energy usage, thicker levels of insulation will be required within the floor construction. This Good Building Guide highlights typical installation techniques, materials, insulation thicknesses and the potential technical risks in achieving improved thermal standards. It covers concrete ground floors insulated above or below the structure, concrete ground floors insulated around the edge, and insulated suspended timber ground floors. Warnings about service entries through insulated floors are given, e.g. water and waste pipes below the floor construction can be damaged by frost, electric cables enclosed within insulation may overheat.