The living room and kitchen in my house share a cathedral ceiling (the rest of the house has standard ceilings). The room gets really hot in summer as there is no ceiling space to create an air gap and presumably no insulation between roof sheets (metal) and the ceiling sheets (fibre-cement sheet).

Does anyone know of solutions for ventilating such a roof so the hot air is automatically extracted? Can whirlybird type devices be installed in this sort of application?

Skylights have been suggested, but those to be opened and closed manually and I want the room to be self-tending.