ABOUT CELLULOSE: Cellulose Insulation is a loose fill material made of recycled newspaper that is typically treated with boric acid to thwart mold, increase fire resistance, and repel hungry insects and mice. Some manufacturers add a moisture-activated acrylic binder that causes the cellulose particles to adhere better, which reduces settling. It is used in wall and roof cavities to separate the inside and outside of a building thermally and acoustically. Having the highest recycled content of any other insulation material, cellulose is a perfect choice for Clean Energy and Green Building.
Cellulose is most often used in attic/roof installations, but can be used in retrofitting old homes by blowing the cellulose into holes drilled into the tops or sides of the walls. An experienced installer can use a dense-pack option that places pressure on the wall cavity which will reduce settling and further minimize air gaps.
Thermally the performance of cellulose compares favorably to other types of insulation. It has an R-value of 3.8 per inch, but this does not represent the whole picture of thermal performance. Other aspects to consider are how well the building envelope is sealed from air infiltration, convective airflows, and thermal bridging. With this in mind, cellulose is very good at fitting around items in walls like pipes and wiring, leaving few air pockets that can reduce the overall efficiency of the wall. Dense pack cellulose can seal walls from air infiltration while providing the density to limit convection, when installed properly.
CELLULOSE & SPRAY-APPLIED CELLULOSE FOR NEW CONSTRUCTION: Spray-applied cellulose is used for applying cellulose to new wall construction. Water is added to the cellulose while spraying as well as adding some kind of moisture retardant such as chlorine to prevent mold cultures. In some cases the insulation might also mix in a very small percentage of adhesive or activate a dry adhesive present in the cellulose. Wet-spray allows application without the need for a temorary retainer, like the blown-in cellulose. In addition, wet-spray allows for an even better seal of the insulated cavity against air infiltration and eliminates settling problems. Wet-spray installation requires that the wall be allowed to dry for a minimum of 24 hours, (or until maximum of 25% moisture is reached), before being covered.
CELLULOSE & SOUND PROOFING: Cellulose Soundproofing is the process of using blown cellulose to pad a room and decrease external noise. The material is so dense that it severely limits sound transfer. It can section off sound from different parts of a house or building so that noise does not bleed from room to room. It is also ideal for musicians because it limits the sound leaving the room and gives the sound a richer tone.
Noise reduction can be achieved in three ways with cellulose. The first is that cellulose completely fills cavities leaving few air pockets for sound to travel in. The second is the cellulose material's ability to trap air. The significant difference between noise reduction with cellulose and fiberglass is it's density. Cellulose is approximately three times denser than fiberglass. This helps deaden the sound through walls and between floor levels. Several installation options allow walls to have a Sound Transmission Class (STC) of 50 or greater. As a comparison, walls with fiberglass batts have an STC of 36-39, depending on stud and screw spacing.