Is It Necessary to Insulate Basement Walls?

Moisture Control

• Blanket insulation is the type of insulation most commonly used on basement walls. Other types of insulation that are available for use include rigid form-board insulation and loose fill. Moisture control is a predominant concern when insulating basement walls, which are in direct contact with the cooler earth. Warm air coming in contact with cold air forms water vapor that potentially leads to the formation of mold and mildew, decay and odors. This creates an unhealthy atmosphere that permeates the entire house. Consequently, a vapor barrier is a necessity when insulating basement walls.

Advantages

• When homes are constructed, insulating the basement ceiling and walls is not a standard procedure. Insulation is generally installed between unheated and heated areas, and the basement is typically considered a heated area. However, there are advantages to insulating basement walls. Insulation on basement walls reduces heat loss through the house's foundation. In regions where there are extreme climate changes throughout the year, insulation protects the foundation against the freeze/thaw cycle. It also reduces the possibility of condensation forming on basement surfaces.

Disadvantages

• Soil often contains more moisture than air, making basements more prone to moisture problems. Insulation on basement walls can exacerbate these moisture problems if not installed properly with a vapor retardant. Exterior basement insulation can attract insects, resulting in possible damage to the home.

R-Value

• If you go through the effort of insulating the basement, you'll want it to produce energy savings. Insulation is measured by its R-value, which is its resistance to heat flow. A higher rating indicates insulation with greater effectiveness. The various regions throughout the United States require different R-values, depending on the climate. Northern regions require R-values ranging from R-10 to R-19 for interior insulation and from R-10 to R15 for exterior basement wall insulation, according to the International Energy Conservation Code, which bases its figures on Heating Degree Days (HDD).