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Blown-in Dense-Packed Cellulose Insulation for the Roof

The roof of the new addition is being insulated to retain all the heat generated from the radiant heating system. Paul Johnson of Alpine Insulators reviews the installation process. The first step involves installing netting that is breathable so air can escape once the cellulose is installed. The netting is fire-retardant and stapled in place to hold dense-packed cellulose in place. Bales of cellulose are emptied into a machine located in an on-site truck that shreds the cellulose before pumping it at high pressure into the cavities of the roof. In this case, the insulation cost about $2.25 a square foot. Cellulose is a great thermal insulator and sound attenuator. In the interior partion wall where the bathroom will be located, cellulose will be installed directly against the drywall. Bill Hulstrunk of National Fiber reviews some of the properties of cellulose insulation, which has been around since about 1920 and used extensively since 1970 in both new and existing construction. Borates are added to make the cellulose fire-retardant, and mold and insect resistant. Because of the added borates, a propane torch can be put to the cellulose without igniting it. In a field test, a penny can be put on top of the cellulose and melted without the heat penetrating the material. These borates are naturally occurring and the cellulose itself is made of 83 percent recycled content, making this type of insulation an environmentally conscious, "green" choice. The cellulose in this house is being used in an unvented application. Because the material is packed very tightly, it reduces the chance that warm, moist air will penetrate the cavity and create mold growth. More information