Cellulose — a material used as loose-fill insulation — is made from recycled wood fiber, primarily newsprint. The wood fiber is shredded and pulverized into small, fibrous particles that pack tightly into closed building cavities, inhibiting airflow. This provides a thermal resistance of R-3.6 to R-3.8 per inch.
This topic includes information related to blown insulation installed during construction. Blown insulation is commonly installed in between studs, joists and rafters. Blown insulation materials include; cellulose, fiberglass and mineral wool.