Basement floors can present a number of problems that are not issues with other floors. Because basement floors lay directly on the ground underneath the house, they are subject to various challenges involving soil, water and seasonal movement. Finishing a basement floor can sometimes make these problems worse by making their solutions more complicated and expensive.
Many basement floors consist of a layer of poured concrete directly on top of subsoil. When the moisture content in this subsoil changes, it can cause the soil to shrink or swell. These changes can cause the basement floor to subside, buckle or heave. If the movement in the concrete is severe enough, the floor may actually crack. This is a difficult problem to solve, although installing proper drainage around the perimeter of the home may lessen its severity. Problems with movement in the subsoil under the house are generally worse in the first 10 years after it is built; after that, the soil usually reaches an equilibrium and doesn't shift and change as much.
Many problems with basement moisture and water are caused by leaks and cracks in the floor that allow the water to move up into the basement area from below the house. At the least this can lead to a humid and mold-friendly basement; if the problem is worse, it can actually lead to basement flooding. If you have a working drain in your basement, it will prevent severe flooding. If you don't, consider installing a sump pump in a pit dug at the lowest point in the floor. Coating the walls and basement with a waterproof concrete compound will solve this problem if it is not too severe.
Basement floors that are finished with subflooring, hardwood, tile or carpet can experience more problems than bare concrete floors. Water and flooding in the basement causes subflooring to rot, hardwood to swell and buckle, and totally destroys carpeting. For these reasons, tile is the best finish material for a basement, although even tile adhesive is damaged by excessive exposure to water. Finished floors don't make the actual problems worse, but do cause you a greater loss when problems occur because of the greater expense that you put into them.