A roof is the highest component of a building that serves as a structural covering to protect the structure from the elements (i,e from rain, sun, wind, etc). Roofs are built in the same way as upper floors in terms of structure, albeit the shape of their upper surfaces may differ. Roofs have been built in a range of shapes and sizes, including flat, pitched, vaulted, domed, and combinations, depending on technical, economic, and aesthetic concerns.
A roof is made up of a structural element that holds the roof covering in place. Trusses, portal beams, slabs (with or without beams), shells, and domes are examples of structural elements. A.C. sheets, G.I. sheets, hardwood shingles, tiles, slates, or the slab itself can all be used as roof coverings.