What is Cellulose Insulation?

Cellulose insulation is the oldest form of home insulation. It can be either a loose-fill or blown-in insulation and can be used in both new and existing homes.

Typical places to use cellulose is in enclosed existing walls, open new walls, and unfinished attic floors. Several companies manufacturer cellulose insulation and it is primarily made from recycled newsprint. These small particles form an insulation material that conforms to most spaces without disturbing the structure or finish.

home insulation

How Cellulose Insulation Works

Cellulose insulation can be used in both existing homes and new construction. It can be blown as loose fill insulation in attic cavities, dense packed into walls and floors, or wet spray for new construction that helps increase heat retention and has the potential to dampen noise levels, according to the Energy Audit Blog.

Dense pack cellulose is used more commonly today for adding retrofit insulation. The dense packing into the wall cavities adds a thermal insulation while providing some level of sound proofing.

Wet spray cellulose has water added to it during the application process. The material has the same thermal and sound retardant properties as dense packing, according to the blog. Wet spray cellulose is almost always installed in new construction before the drywall is put up.

Process of Installing Cellulose Insulation

Cellulose insulation can be installed by one of two techniques. It can be blown-in – loose fill or dense pack. It can also be spray applied with moisture added.

The dry blown insulation can be installed using a machine to blow the cellulose into the area to be insulated.

In existing homes, installers will remove a strip of exterior siding around waist high. They will then drill a row of three inch holes – one into each stud cavity. A special filler tube is then inserted and the insulation is blown-in filling the cavity. When installation is completed, the holes are sealed with a plug and the siding is replaced.

For new construction, cellulose can be either damp-sprayed or installed dry behind netting, according to the U.S. Department of Energy.

When  cellulose is damp sprayed, a small amount of moisture is added at the spray nozzle tip, adding natural starches in the material causing it to adhere to the cavity.

blown cellulose insulation


  • Cellulose has more recycled material than any other commercially available insulation.
  • Cellulose doesn’t use any greenhouse gases as propellants.
  • When blown into stud cavities cellulose gets into most all the nooks and crannies.
  • Cellulose insulation is very inexpensive.
  • Boric acid, borax or aluminum sulfate used in cellulose insulation provide resistance to mold, pests, and fire.
  • A machine can be rented at most local home improvement stores to blow cellulose insulation into an attic, making it a weekend DIY project for the experienced homeowner.


  • Modern cellulose settles up to 20 percent, which is problematic in relation to closed cavities causing the home to be uncomfortable and energy bills to rise, according to House Energy.
  • Cellulose must be kept dry as it absorbs up to 130 percent water by weight.
  • It dries very slowly after absorbing water, causing it to deteriorate and settle afterwards.
  • After cellulose insulation absorbs water, the chemical fire treatment is destroyed.
  • Dense packed cellulose gets everywhere spilling into the house through any openings in the wall cavity.
  • Homes with furnace duct systems can expect some of the cellulose dust to be recirculated through the house.
  • Cellulose weighs several times as much as fiberglass, which isn’t an issue unless insulating an attic slope.
Baffle installation
Spend Time Doing What You Love, And We Will Too; After Purchase We'll Install The Baffles For You!

We start off every project with a free estimate. We study the space, and talk with you about all options so you know what decision is best for you. 

I am text block. Click edit button to change this text. Lorem ipsum dolor sit amet, consectetur adipiscing elit. 

We stand behind our products; With us you get a 10 year warranty on the job and a 5 year warranty on the product.

Follow Us

  • Facebook
  • Twitter
  • YouTube
  • Instagram


  • Insulation
  • Heating
  • Duct Services
  • Air Conditioning & Cooling
  • Solar Fan
  • Water Heater

Our Company

  • About us
  • Our Work
  • Our Team
  • Insulation Blog

or call us at


Copyright 2018 © All rights Reserved Green Attic Insulation

Close Menu
Call Now!