Cellulose is a material used as loose-fill insulation 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.
Cellulose insulation is considered a green building material because recycling paper has a big impact on the environment. Paper and paper products make up the largest percentage of material deposited in municipal landfills, up to 38% material deposited in landfill! For every 1 ton of paper recycled and reused, 3 cubic feet of landfill space and 17 trees of lumber are saved.
Cellulose insulation is a blown product, so it is easily blown into irregular or hard-to-reach spaces, but contains no harmful emissions during or after installation, contains no formaldehyde, and is mold-resistant. It is not water resistant, but it has water wicking characteristics.