There are many reasons why you should use a basement vapor barrier after you have insulation the area. A protective sheet over the basement floor will prevent moisture from rising into the walls. The basement vapor barrier will inhibit the rot, mold, and water damage in your walls.
Reasons to Use a Barrier
If you have recently applied a new layer of insulation after the previous one was infected with mold, or because it had become sodden with water, you may find a barrier useful. The plastic sheet will stop the basement walls from becoming damp, which will then stop the moisture from rising into the rest of the house and warping your floorboards. In areas with a low water table, a basement vapor barrier can prevent water damage to the rest of your home.
Reasons Not to Use a Barrier
You may experience problems fitting the plastic barrier if you have a lot of electrical outlets, ducts, and other connections. Some problems with installing insulation which is pre-fitted with a vapor barrier, include putting the barrier in so that it faces upwards, rather than towards the bedroom, meaning that the barrier will be much less effective than usual.