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Walls are built to enclose areas and carry the weight of floors and roofs. The walls may be solid or hollow. The materials used for the wall construction can be brick, stone, concrete and other natural and artificial materials.
Roofs cover the building and protect it from exposure to weather. They tie the walls and give the construction strength and firmness.
They may be either of timber or of a fire-resisting material.
The floors, walls, roofs and other parts of the building must be carefully designed and proportioned
Floors divide the building into stories.
The walls can be solid or hollow.