A. Inadequate structural design. The building cannot perform the task to which it was put. B. Later changes that render the structure inadequate for the job to which it is put. Changes to the structure. Changes to the uses a building receives.
Buildings also fall down because the materials of the building themselves deteriorate.
There are five reasons that building materials fail, acting either alone or together with other causes they will ultimately cause the building to collapse. It is in the nature of materials to change, losing their flexibility, adhesiveness, tensile strength, porosity or impervious character. It is the effect of gravity that pulls relentlessly upon stones, or boards and that requires fasteners to retain materials in their place. All materials expand when heated and contract when cooled and each material responds to these variations at its own rate. Light and heat fade and make materials brittle materials.