semipro
Member
Air sealing is more more important than thermal insulation in most structures, whether house or bus. Fiberglass does no air sealing although it will filter the air that leaks through. This is typically manifested as gray stained areas in the insulation. Also, foam, whether sprayed or board acts as a moisture retarder. Its easy to visualize the warm moist air in a bus passing through fiberglass insulation and condensing on the cold steel walls. Loss of thermal insulation value and mold can result. Sprayed or board foam installed and sealed can prevent this in addition to providing more thermal insulation per inch thickness.
