Exterior Wall Construction Vapor Barrier

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.

Exterior wall construction vapor barrier.

If you are adding an exterior wall anywhere in the house and you answered yes to either of the above questions you should consider using a vapor retarder. Verifying the vapor barrier location and the thermal performance of the insulation relative to the dewpoint location. Determining the dewpoint for the interior environment locating the dewpoint in the wall construction. This wall assembly will dry from the vapor barrier inwards and will dry from the vapor barrier outwards.

A vapor barrier reduces the movement of water vapor by. 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. 1 the fundamentals of creating a proper vapor barrier include developing the thermal section of exterior wall or roof. 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.

Where is the wall located. If dow and the other companies are correct in their information that a perm rating of about 10 is ideal for the exterior water vapor retarder for mixed humid climates then this would be a material that keeps out nearly 100 of wind driven rain water yet allows any. In hot climates any moisture that condenses on the exterior side of the vapor barrier will be drained to the exterior since the vapor barrier is also a drainage plane. Let s consider the exterior water barrier vapor barrier retarder first.

Most authorities recommend vapor barriers in certain situations. In exterior walls that are below grade like basement walls. Vapor retarder use and placement. In areas with high humidity such as greenhouses rooms with spas or swimming pools and bathrooms vapor barriers are often recommended.

The standard installation of a plastic vapor barrier is between the studs and the drywall but there are some exceptions to this. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. Avoid adding interior vapor barriers where the outer wall construction already includes a material with vapor barrier properties.