Pretty Finished Basements - There are numerous approaches to help avoid moisture damage issues in a cellar. The very first rule of thumb is no dirt basements. Although these are less prevalent in this day in age, it's a good idea to point out that dirt floors not just hold a large amount of moisture but can also give off a number of gases. When building a cellar, make certain that you have a floor drain with a trap installed in the bottom point of the floor.
With no floor drain, any water that is spilled inside cannot escape. If necessary, install a sump pump and make sure that the sump cover is tightly sealed. Sump pumps are often used where flood due to a high water table may be a problem. Additionally, waterproof the exterior of the foundation walls and install a perimeter drainage system. A frequently overlooked problem in bathrooms is moisture that comes from humidity.
The simplest way to control humidity would be to exhaust water vapor produced in the home to the exterior. Indications of high humidity include condensation on walls, pipes or other surfaces as well a general sense of moisture in the air, dampness, and odors. Many times, the humidity is going to be brought on by exposing the cellar to outside air (open windows), using wet laundry hung to dry in the cellar, keeping firewood in the cellar, or a dryer vent that exhausts indoors.
In hot, humid weather, keep cellar windows closed. Run the furnace fan continuously to circulate home air. The real key to keeping basement humidity low would be to keep them well ventilated and to keep extra moisture out of the cellar.