Sprayed Cellulose (“moisture added”) insulation

Moisture-added cellulose insulation is often used in new construction. The cellulose is sprayed directly into the cavities, between the studs and against the exterior sheathing, filling them completely, leaving no gaps or voids.

As the dry cellulose insulation is blown from the applicator hose, a small amount of water is added, activating the starches in the cellulose so it adheres to the surfaces within the wall and ceiling cavities. Just enough water is added to ensure good adhesion within the cavity.

The wall cavity is actually overfilled, until the cellulose extends beyond the face of the studs or rafters. The excess material is removed using a rotating scrubber brush, leveling the insulation with the face of the studs or rafters. The small amount of moisture added dries quickly, usually within 24 to 48 hours, and is then ready for drywall. The excess material is vacuumed from the floor and recycled back to the blowing machine by a return hose.

Because this technique requires very specialized equipment and training, it must be performed by experienced installers.