When upgrading an existing ceiling in an historic building, pub or flats where there is no access to the ceiling from the room below; a combination of 12mm thick SUPALUX® board and 75mm deep support strips fixed to the sides of the joists, along with minimum 80mm thick x 23kg/m3 stone wool insulation can provide up to 60 minutes of fire resistance (fire integrity and fire insulation). The system can be applied for applications where the fire risk is from below but where it is only possible to carry out work from above the floor. For detail, please see page 114 (Fig 4.30.2) in Chapter 4: Ceiling, Floors and Roofs.