Information pulled from the Department of energy website
Cellulose insulation is made from recycled paper products, primarily newsprint, and has a very high recycled material content, generally 82% to 85%. The paper is first reduced to small pieces and then fiberized, creating a product that packs tightly into building cavities, inhibits airflow, and provides an R-value of 3.6 to 3.8 per inch.
Manufacturers add the mineral borate, sometimes blended with the less costly ammonium sulfate, to ensure fire and insect resistance. Cellulose insulation typically requires no moisture barrier and, when installed at proper densities, cannot settle in a building cavity.
Cellulose insulation is used in both new and existing homes, as loose-fill in open attic installations and dense packed in building cavities such as walls and cathedral ceilings. In existing structures, installers remove a strip of exterior siding, usually about waist high; drill a row of three inch holes, one into each stud bay, through the wall sheathing; insert a special filler tube to the top of the wall cavity; and blow the insulation into the building cavity, typically to a density of 3.5 lb per cubic foot. When installation is complete, the holes are sealed with a plug and the siding is replaced and touched up if necessary to match the wall.
In new construction, cellulose can be either damp-sprayed or installed dry behind netting. When damp sprayed, a small amount of moisture is added at the spray nozzle tip, activating natural starches in the product and causing it to adhere inside the cavity. Damp-sprayed cellulose is typically ready for wall covering within 24 hours of installation. Cellulose can also be blown dry into netting stapled over building cavities.
Learn more at the Department of energy