The structure may be concrete or metal. Nevertheless, precast concrete beams are normally used for spans of up to 10m, with metallic beams used for greater spans (up to 13.30m).
The roof is attached either directly to the structure (if it has the correct angle) or by using a special support edging that sits on the roof at the required angle.
There are two types of tension bar that can be used in this type of roof, each with different objectives.
Tension bars are necessary for spans of more than 10m and, above all, in those buildings with metallic support structures.