To dream of a building symbolizes your physical being. Your state of comprehension is indicated by which floor of the building you are on. If you are in the lower levels of the building, the dream reflects your base desires, sexual wants and needs.
To see a ruined or damaged building implies that you need to tackle a problem or issue in a different method. Your current system is proving to be unsuccessful. You must make major alterations. Perhaps your ego has been damaged.
To dream that you or someone falls off a building implies that you are beginning to understand the various aspects of your personality. It may also represent your anxieties regarding your ability to finish a project or reach an objective.