Before the introduction of plastic and fibre glass as material for rooflights, the majority of rooflights to flat roofs were constructed as lantern lights or deck lights which were framed in timber or steel and covered with glass.
A lantern light is constructed with glazed vertical sides and a hipped or gable-ended glazed roof. The vertical sides of the Lantern light are used as openings for ventilation.
Lantern lights were often used to cover considerable areas, the light being formed with substantial timbers or iron and steel frames in the form of a glazed roof to provide top light to large stairwells and large internal rooms. The traditional lantern light of timber or steel requires frequent or careful maintenance if it is to remain sound and watertight.