For many people, the concept of roof and roof is one and the same. But this is not so. The roof is a component of the roof, and the concept of the roof implies the upper protective coating of the entire building of the building. Based on this, we can understand that the roof is a complex structure, which consists of an external coating (roof) and internal supporting part. There is not a single full-fledged building without a roof, but if there are walls without a roof, then this is a fence of a site.