Over spanning of the joists that support your property’s main floor is a serious issue that can have varied and unexpected side effects. As well as the obvious sag and unevenness that will develop in affected floors, there are other, arguably more serious issues to consider.    Leaning or Bowing Walls     Leaning and bowing walls are a fairly common side effect of over spanned joists. That’s because, when a floor begins to sag in a pronounced way, it can pull away from the wall. This will cause the wall to be destabilized and, over time, the wall will deviate from its intended position. When this happens, it will actually cause further damage to the floor.    As such, these two issues are often connected and can form a somewhat vicious cycle. As a result, the joists will become weaker, causing the floor to sag further and the walls to bow or lean more severely. This can lead to issues with dampness and drafts, but also more serious repercussions, like the total collapse of certain walls or sections of flooring.    Floor Collapse    If left to percolate without intervention, over spanned floor joists will eventually lead to the collapse of the floor, either in sections or in totality. This is dangerous for obvious reasons. Any people, animals, or even furnishings in a room when this happens will face serious injury or damage. With that said, there are other, more long-lasting effects.    The floor joists may primarily support your flooring, but they play an important role in supporting the structure of your home overall. When a section of a property’s floor collapses, even in isolation, the rest of the structure will be put under pressure or left with insufficient support. As a result, you may find that walls or even upper floors are in danger of meeting the same fate if you don’t act quickly.