Abstract: A prefabricated balcony platform including attachment members to fasten the platform to the wall of a building, and apertures to secure a parapet to the platform. The balcony platform consists of a load-carrying beam frame of a corrosion-resistant metal, such as aluminium, a bottom slab of refractory material attached to the lower face of the beam frame and a top slab attached to the upper face of the beam frame and consisting of a material having heat-transfer properties, preferably aluminium. In the beam frame intermediate the two slabs is provided a layer of sound-proof, refractory material, such as mineral wool.