Blown-In Insulation

Blown-in insulation (Figure

3- 10) is a loose-fill insulating material, typically fiberglass, rock wool, or cellulose (see Figure 3-9 Loose-fill insulation. Loose-Fill Insulation). The insu­lation material is blown under pneumatic pressure into the spaces between joists and wall studs in an existing structure. Water vapor retarders are applied first and are available in the form of a moisture-resistant, spray-on paint. Blown-in insulation is most commonly used to insulate interior walls, especially in existing structures. Blown-in insulation also can be used in new construction, but the wall cavities first must be covered with tempo­rary containment sheeting to hold insulation in place. The insulation is then blown into the wall cavities, and the studs are covered with the appropriate finishing material.

Table 3-4 Loose-Fill Insulation R-Values

Type of Loose-Fill Insulation

R-Value per Inch Thickness of Insulation

Fiberglass loose fill insulation

R-2.3 to R-2.7

Rock wool loose-fill insulation

R-2. to R-3.0

Cellulose loose-fill insulation

R-3.4 to R-3.7





Figure 3-10 Blown-in insulation.

figure 3-10 blown-in insulation.

Because special equipment must be used for its applica­tion, blown-in insulation should be applied by individ­uals trained in its use.

Posted in Audel HVAC Fundamentals Volume 1 Heating Systems, Furnaces, and Boilers