To see a building in your dream represents the self and the body. How high you are in the building indicates a rising level of understanding, awareness or success. If you are in the lower levels of the building, then it refers to more primal attitudes and/or sexuality. 

To see a building in ruins or damaged indicates that your approach toward a situation or relationship is all wrong. You need to change. Your own self-image may have suffered and taken some blow.

To dream that a building collapses indicates that you are losing sight of your ambitions and goals. Your pursuit for material gains is failing.

To dream that you or someone fall off a building suggests that you are descending into the realm of subconscious. You are learning about and acknowledging aspects of your subconscious. Alternatively, it symbolises your fear of not being able to complete or succeeding in a task.  See also Falling in our Common Dream Themes section