The invention is a method comprising the steps of wetting insulating materials with an aqueous solution containing an amount of a mold inhibitor such as chlorine, in an amount effective to inhibit microbial growth on the materials, and in one form, sterilize existing microbial growth in the cavity in which the insulating materials are to be placed; and placing the insulating materials into a portion of the structure. The method provides an advantageous and low cost process for the placement of wetted insulation materials that reduces the time required to complete closure of the insulated portion of the building while (1) minimizing the risk of undesirable growth of molds, fungi and the like and (2) sterilizing surfaces contacted by aqueous solution or wetted materials.