Moisture Barrier Insulation Walls

Cover exposed foundation walls with 1 1 2 in.

Moisture barrier insulation walls.

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. If you live in a cold climate place the vapor barrier between the interior of your home and the insulation. Holes in the vapor barrier that allow humid air through may allow a lot more water vapor into an assembly than the vapor barrier is stopping. After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one.

This not only insulates the walls but also keeps rising dampness in the concrete from getting into the crawlspace. Vapor barriers keep the air moisture in your house from condensing in the insulated cavities. Water vapor can pass through building materials in several ways including direct transmission and by heat transfer but studies suggest that fully 98 percent of the moisture transfer through walls occurs through air gaps including cracks around electrical fixtures and outlets and gaps along baseboards. Whether or not you need a vapor retarder hinges on three main factors.

A vapor barrier reduces the movement of water vapor by diffusion. As mentioned earlier batt and roll insulation come with a vapor barrier attached. Vapor barriers applied over the face of the insulation provide additional benefits in the fight against moisture. Without a vapor barrier in place condensation inside the walls could ruin the insulation and promote the growth of harmful mold and bacteria.

Thus installing vapor barriers on wall surfaces must. In any case the vapor barrier must point to the warm side. A vapor barrier is designed to keep moisture in your home from getting inside your walls. Whether your vapor barrier is a facing or a film it must be placed on the warm in winter side of the wall.

However leakage can occur where the facings meet. Not every wall does. Applicability limited to very cold subarctic and arctic regions. We used thermax brand available through lumberyards of polyethylene vapor barrier because it doesn t require an additional fire barrier.

Plastic specifically 6 mil polyethylene plastic is. This wall is a further variation of figure 6 but now it has a class i vapor retarder on the interior a vapor barrier completely eliminating any inward drying potential. Frame wall with cavity insulation and brick or stone veneer with interior vapor barrier. Of rigid moisture proof insulation.

The science of moisture movement. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.