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Cellulose Insulation Manufacturers Association
Installing cellulose insulation in attic dry blow in 4090
Attic Dry Blown In - Cellulose Insulation

Dry Blown-In Cellulose Insulation


There are two techniques that can be used to install cellulose insulation: loose-fill for open attics and dense pack for enclosed framed cavities. Loose-fill is the least complicated option for homeowners interested in a do-it-yourself (DIY) cellulose installation. Dense packing cellulose in enclosed framed cavities is more complicated and almost always done by a qualified professional insulation contractor.

Dry blown-in is the most common type of cellulose installation. It involves feeding loose-fill cellulose insulation into a blowing machine which blows the fiber through a long hose to the desired area of application. The process requires at least two people, some basic technical skills and a good understanding of the space to be insulated.

Open Attics

A flexible hose is used to dry blow cellulose insulation fiber into open attics.

Blow the amount of insulation, specified by the chart on the bag, evenly throughout the attic to achieve the correct R-value. Before installing, be sure to prepare the attic space to properly receive the dry blown-in insulation.

TIP: If there is existing insulation that is deteriorated, wet or moldy, it should be removed. If there is already blown-in insulation in place, cellulose can be blown over the top to increase the R-value and overall performance. In attics with fiberglass batts, the batts should either be removed, or the cellulose blown under the batts to make contact with the ceiling below. For best performance, the cellulose should cover any existing insulation and framing.

Safety & Comfort: Installing cellulose can be dusty, so wear a dust mask and goggles.

Enclosed Wall

Dense packing of enclosed walls is a complicated installation process. It is usually installed for retrofitting cellulose into existing homes and buildings. This type of installation requires specialized tools like flexible wall hoses and a machine capable of producing a minimum of 2.9 psi pressure from the hose outlet of the machine.

For these reasons, CIMA does not recommend homeowners attempt dense pack installations. Hiring an experienced insulation installer is highly recommended. Click here to find CIMA Producer Members that can refer contractors in your area familiar with installing cellulose insulation products. You can also check with your local utility company, the Yellow Pages or other online sources for insulation contractors.

Insulation Contractor dry blow-in installation of cellulose insulation