Exterior Stud Wall Vapor Barrier

How to insulate house walls from the outside.

Exterior stud wall vapor barrier.

Window door openings connect both walls with 1 2 underlayment plywood and are sealed to the vapor retarder air barrier. In exterior walls that are below grade like basement walls. Not every wall does. 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.

It may look easy to go buy some packs of rigid insulation panels down at the. Since this wall assembly has a vapor barrier that is also a drainage plane it is not necessary to back vent the brick veneer reservoir cladding as in figure 6 and figure 7. Moisture driven inwards out of the brick veneer will condense on the. Adding extra insulation to the exterior walls of an older home when renovating or remodeling is a great way of improving a home s walls thermal performance and reducing energy use while reducing heating bills carbon footprint and improving a building s comfort level.

Your first job after the studs are in place is to fill those walls with insulation. 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. The exterior face of the wall or floor cavity should remain permeable in order to allow dissipation of any moisture that does enter the wall cavity. The standard installation of a plastic vapor barrier is between the studs and the drywall but there are some exceptions to this.

If you put a polyethylene vapor barrier behind a drywall covered stud framed wall then the answer is that water that condenses on the poly will fall onto the wood sill plate growing mold and eventually rotting it out. This will give you two vapor barriers one before and one after the stud wall framing. The other option is to set the 2 4 wall framing in 4 from the masonry or concrete basement walls and use just the vapor barrier on the insulation facing toward the living space. This is then followed by a 2x4 wall with studs offset from exterior wall another 3 1 2 fiberglass or rockwool then sheetrock.

This wall assembly will dry from the vapor barrier inwards and will dry from the vapor barrier outwards. 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. Very hot and humid climates may benefit from an exterior vapor barrier that keeps outside humidity from penetrating into walls. If you are not sure if you need insulation in your walls follow along with this flow chart.

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. Dedicated vapor barriers have no place in a basement wall.