Cellulose is one of the oldest types of building insulation materials and has been made from numerous materials including cardboard, sawdust and hemp. Modern day cellulose is made from recycled newspapers and treated to be fire, pest and mold resistant. Cellulose has an R-value of approximately 3.8 per inch and is excellent at reducing sound. At Caddis, we use cellulose mainly to fill existing wall cavities and to insulate attic floors. Cellulose can be installed loosely, like on attic floors, or dense packed in existing cavities. In order to prevent settling, dense pack cellulose must be installed at 3.5 inches per cubic foot. Cellulose can be installed in new construction projects by first installing a netting to contain it prior to drywall install.
Cellulose is an excellentsound deadening material. Like spray foam, it fills and forms to fit any sized and shaped cavity. Dense pack cellulose is an air barrier while loose fill allows air infiltration. For this reason, a proper attic insulation job includes air sealing all gaps and penetrations with foam insulation. Cellulose is generally slightly less expensive than open cell foam.