Insulating Interior Basement Walls Vapor Barrier

Basement vapor barrier and insulation.

Insulating interior basement walls vapor barrier.

If you have a framed wall that is adjacent to a concrete foundation wall where the vapor barrier is next to the drywall in front of the studs the fiberglass insulation gets wet and becomes a breeding ground for mold. I planned to install vapor barrier on top. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. Not to be confused with a vapor barrier which is placed on the warm side of the wall just in front of the insulation and behind the drywall a moisture barrier goes against the basement wall.

Whether or not you need a vapor retarder hinges on three main factors. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter. On the interior the best insulation to place against the concrete or block is rigid foam without any facing such as foil or plastic sheeting. The construction of the wall for instance is vital to the use of a vapor barrier.

In any case the vapor barrier must point to the warm side. The place to control vapor migration is on the exterior of the basement wall in the form of waterproofing or damproofing. For reference my basement is currently finished with concrete exterior walls then charcoal colored wrap material there seems to be an inch or two between this wrap and the exterior walls then stud framing with r12 batt insulation between the studs then a vapor barrier and finally drywall on top of the vapor barrier. Is it ok to add this vapor barrier.

When a vapor barrier is on the side of a wall where the dry air is i e outside in winter or inside in summer moisture problems can occur. Bathrooms and kitchens produce an enormous amount of water vapor daily. A vapor barrier s job is to keep water vapor in humid air from diffusing through one side of a wall and finding a cool surface inside the wall. We ve written several articles about basement insulation and a cost effective approach to basement insulation using foam board and fiberglass insulation since writing those articles we ve received quite a few questions about when to use a basement vapor barrier and when not to.

The short answer is no you generally do not want a vapor barrier on the walls of a finished basement. I live in central ontario canada. This barrier is meant to keep moisture from getting to the insulation in the walls and ceilings and it is required by building codes when insulating most houses. A vapor barrier reduces the movement of water vapor by.

Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. When the mold grows it will spread to. So we thought it might be a good idea to clear up some of the confusion. My basement wall is insulated with a 2 inches of styrofoam on the interior and i built a 2 4 wall and added roxul insulation.