Foundations are the set of elements of a structure, whose objective is to transmit and distribute the load it supports to the ground so that it does not exceed the weight it supports.
The structure of your building or ‘skeleton’, as it is often called, is made up of several elements. The structural elements are usually: slabs, pillars, walls and beams. They are what keep the building standing both by its load in the horizontal and vertical planes. The roof is the set of construction elements that form the upper part of a building, it is part of the building envelope.