Ancient Roman Roofs
The way of construction of ancient Roman roofs (tecta) differed little from modern methods. Roofs varied as much as ours do in shape; some were flat, others sloped in two directions, others in four. In the most ancient of times the covering was a thatch of straw, as in the hut of Romulus (casa Romuli) on the Palatine Hill, preserved even under the Empire as a relic of the past.
Shingles followed straw, only to give place, in turn, to tiles. Tiles were at first flat, like our shingles, but were later made with a flange on each side in such a way that the lower part of one would slip into the upper part of the one below it on the roof. The tiles (tegulae) were laid side by side and the flanges covered by other tiles, called imbrices, inverted over them. Gutters also of tile ran along the eaves to conduct the water into cisterns, if needed for domestic use. The appearance of the completed roof is shown in the picture.
Roman Tile Roof.