Basement Wall Insulation Vapor Barrier

Whether or not you need a vapor retarder hinges on three main factors your climate your home and the location of the wall you re insulating.

Basement wall insulation vapor barrier.

After the insulation is in place you will want to add a vapor retarder sometimes called a vapor barrier if you need one. The best option for insulating a basement is to use spray foam insulation. The foam layer should be continuous and sealed at joints to keep indoor air away from the concrete. The material is stapled to the frame of a basement wall before it is finished with plaster or drywall.

The construction of the wall for instance is vital to the use of a vapor barrier. Of foam against the wall this should not be a problem in your climate. But if you use. A vapor retarder is a material used to prevent water vapor from diffusing into the wall ceiling or floor during the cold winter.

In any case the vapor barrier must point to the warm side. When the mold grows it will spread to everything around it studs drywall etc. 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. It provides the best coverage and r value and and functions as a moisture barrier in and of itself.

Basement insulation vapor barriers the trick with basement insulation jobs is in understanding where water vapor is being stored and where it s moving to. Vapor barriers are sheets of plastic or other material placed on one side of insulation sheets. 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. Concrete is like a huge sponge which holds water and water vapor for years and years.

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. This will give you two vapor barriers one before and one after the stud wall framing. Also be sure to use treated lumber for the bottom plate on the wall framing. With fiber insulation and a vapor barrier moisture can get trapped in the insulation leading to moldy insulation and decay in the wood framing.

A vapor barrier is also helpful to keeping a basement insulated and warm. The builder insulated the upper 4ft of the basement wall with a pink batt style insulation which is held to the wall with a vapor barrier. The vapor barrier is sealed to the concrete wall at the bottom with some sort of seal and nailed directly to the concrete.