The purpose of insulation is to reduce convection, conduction and radiation heat losses within the home. Good insulation is one of the homeowner’s best defenses against high fuel bills. Considering present liabilities and health concerns regarding types of insulation, it is important for a real estate agent to be able to recognize and evaluate them.
TYPES OF INSULATION
Glass Fiber Insulation is one of the most common and is made from threads of glass and formaldehyde. It is available in blanket or batt form, as well as loose fill. It is resistant to moisture, mildew, fungus, and vermin, and is generally considered non-combustible. During installation it is a skin irritant, and inhaling the small threads of glass fiber can affect the respiratory system. Cost: less than $.80 per sq.ft. for R-19 uninstalled.
Mineral Fiber or Mineral Wool is similar to glass fiber except that rock or slag is used to form the wool like texture. Like glass fiber insulation it resists fire and rot, and is less irritating to work with than glass. Cost: approx. $1.00 per sq. ft. installed.
Cellulose Fiber is made from paper, finely shredded and treated with chemicals to make it somewhat resistant to moisture, fire rot and vermin. It is usually blown in, but can also be poured. It is usually grey in color and is similar to lint from a dryer in texture. Though cellulose fiber is inexpensive, it will absorb water which will lead to deterioration. Cost: $2.00-$3.50 per sq. ft. (blown in).
Vermiculite is a mineral substance made from mica It is available as loose fill and can be recognized by the small individual rectangular pieces. It is non-combustible, subject to moisture damage and relatively expensive. It is used in block cavities in commercial construction.
Plastic Board Insulations are made from polystyrene, or polyurethane. Both pose fire hazards if left exposed. If applied on interior or exterior walls, they should be covered by at least a half inch drywall or plaster. They have the highest R-value, and are more expensive than most types. Cost: $1.00-$2.00 per sq. ft.
Urea Formaldehyde foam insulation was used extensively as a residential insulation in the mid-1970s. UFFI was banned in Canada in December 1980, because of suspected health hazards. Formaldehyde gas is an irritant and may be carcinogenic (cancer causing). Colors and textures of UFFI vary, but it can be distinguished from other foam insulations by its crumbly structure and powdery residue. Positive identification can only be done by laboratory testing. Cost to remove: $20-$35.00 per sq. ft.
Asbestos is an effective insulator against heat, cold, electricity and noise. In the late 1960s and early 1970s, it was used extensively for residential and commercial insulation. Under the Construction Safety Act of 1973, both the practice of spraying asbestos and using it for pipe and boiler wrap were prohibited. Asbestos insulation that has not been disturbed is not considered a serious health threat. When used as a pipe or boiler wrap, the heat causes the asbestos to become increasingly fragile. When asbestos becomes friable (crumbly to the touch), then it becomes air borne and presents a health concern. Asbestos is carcinogenic and where friable asbestos insulation is present, removal is strongly advised. Cost of removal: $20-$35.00 per sq. ft.