Monday, December 14th, 2020 by Ashley Walther
When installing insulation in a closed wall or attic, it will likely be a loose-fill blow-in cellulose insulation. While there are other options, (such as fiberglass batts), cellulose is the most cost-effective and environmentally conscious method.
Cellulose insulation is a wood or paper-based product that is blown in to empty spaces in the structure of the home to slow the transmission of conditioned, heated air out of the home and cold, outside air into the home.
With a consistency much like down feathers, cellulose insulation is dense and clumpy. This type of insulation can fit in enclosed areas and can mold itself around obstructions like wires and ducts found in both walls and attics. Technically speaking, cellulose insulation can come from any cellular plant source. Commercial cellulose is usually derived from wood or paper products: recycled newspaper, cardboard, printer papers and other waste paper products. Because of this, cellulose is considered an eco-friendly home product.
Cellulose insulation is usually installed as a loose-fill, meaning that the cellulose is dry and loose. Bales of cellulose are fed into an insulation blower, powered by an electric motor. Rotating teeth or prongs tear up the cellulose to fluff it up prior to blowing. Long, flexible tubes blow the cellulose into the attic or walls. Cellulose can fill cavities in these spaces, or it can blanket over existing insulation. No pressure is place on the cellulose; it settles over time.
Cellulose insulation has a number of advantages over other types. Cellulose insulation settles around and conforms to typical obstructions found in attics and walls. It's relatively inexpensive but still has an R-value of around 3.5 inch of thickness. In comparison, fiberglass has an R-value of R3 to R4 per inch. Cellulose is an excellent choice to stand up against vermin and pests, because it is treated with borates. This is why it's not flammable, too!
Cellulose insulation can be considered a "green option" because it uses up to 85% recycled material.
During the manufacturing process, cellulose insulation is treated with borates. Borates are a Class I fire retardant. It's possible to use a blowtorch to warp a penny resting on a bed of cellulose insulation. The cellulose will remain unaffected, even as the penny begins to melt!