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How To Insulate Older Home Attic With Cellulose

It’s not really hard to determine whether an old home needs new attic insulation. If there is room enough to get a look in the attic it’s pretty easy to tell. Recently we purchased an historic 1940’s era home for use as an office.

Photo of existing attic batt insulation

Old batts had settled and deteriorated.

Going in it was clear the property needed renovation. A look in the attic confirmed a major upgrade item would be insulation. The old fiberglass batts had settled well below the tops of the joists and the overall coverage was providing limited insulation (RValue) at best. This also provided an excellent opportunity for me to personally experience the retrofit insulation process from a consumer perspective. Here’s a recap of that experience:

Selecting Insulation and Installer:

My goal was to increase the insulation to R-30 for long-term energy savings and to obtain a rebate from the local utility company.  The best options were to add another layer of fiberglass batts or to have fiberglass or cellulose blown in. I decided to blow in insulation. It would be more expensive but provide much better coverage and help to control air infiltration. I obtained bids from three reputable insulation contractors and was surprised to learn that their was no difference in price between cellulose and fiberglass. After reviewing references on each I select the mid-priced bidder and chose cellulose for it’s environmental benefits and excellent insulating characteristics.


Once the job was scheduled it was time to take a harder look in the attic. It was important to inspect and make any repairs before almost 10 inches of cellulose insulation was blown over the old batts and everything else. I suited up in protective gear (their was quite a bit of “fiberglass dust” from the existing batts in the attic) and cleared out old items, shored up A/C ducts and made other minor repairs and preparation. Then, prior to installation day I also covered the just-restored original wood floors with 6mil visqueen. The attic access was in the bathroom ceiling accessible via a long hallway from the front door.

Photo of cellulose insulation in attic

After Cellulose Insulation Install


My insulation contractor did an excellent job.  Their three-man crew closed off the doorway between the hall and bathroom with more visqueen. Then they carefully ran their blower hose through an opening and up into the attic. The job took about three hours and 40 bags of cellulose insulation for my 1,030 square foot house. There was no spilled cellulose and surprising very little fiber dust. A quick run of the vacuum in the bathroom was all the clean up required.

Cost & Outcome:

My cost after the rebate was $410.00. It will be a few months before I can compare utility bills but I feel this was an excellent investment in my property. We have already noticed the house is much quieter and the inside air temperature is more stable. Overall, after just a few weeks, the living environment has clearly improved.

Maybe it’s time to look in your attic. If you haven’t recently it probably will raise questions. Leave them in the Reply box below and we’ll try to provide answers.  Have your own insulation story? Share it in the Reply Box with our readers.

(Jim Doyle works with CIMA team to write and edit the Greenest Insulation Blog. The office referenced in this story is in Jacksonville Florida.)


2012-01-29 22:18:55
Insulation Dallas says:

I was very surprised by your comment that there was very little fiber dust when blowing this insulation. When we blow cellulose there seems to be an abundance of dust from the product. We are not operating the equipment at high speeds or anything and are using a 4" delivery hose.

Insulation Dallas

2012-01-30 09:53:32
Dan Lea says:

Some fiber insulation materials are dusty, others, including many cellulose products, produce virtually no dust during installation. Apparently the cellulose insulation installed in Mr. Doyle's office was a low dust material.

2012-02-07 09:36:55
CIMA Admin says:

We did quite a bit of preparation for the installation as noted in the story including sealing off the room with the attic access. The attic access was in a bathroom which made controlling dust easier as well. Prior to starting the blower the shower was run which added moisture to the area to help collect dust. The insulation was also blown with a slight bit of moisture added to help control dust as well. The window in the bathroom was also open with the screen removed to aid in ventilating.

The end process was a very low level of dust in the bathroom which was easily cleaned up. The remainder of the house was virtually dust-free.

Thanks for your comment.

2012-04-16 19:51:24
Barry Pendley says:

Hi Insulation Dallas:

Cellulose can be dusty, but it looks like these contractors were careful to minimize the dust in the house.

For those who have dust issues with cellulose, there are at least two other ways to minimize the dust:

First, make sure that you are not using stabilized cellulose that is designed for wall spray. It includes a starch that will create a lot of dust in an open, dry blow situation.

Second, many installers are using an internal wetting system for insulation blowers. This adds a mist of water to the material which controls the dust in the attic and creates a nice stabilized crust after it dries.

2012-04-17 17:34:40
CIMA Admin says:

Good comments and suggestions Barry. That is pretty much what my insulation contractor did. In Florida we always have concerns with moisture due to the humidity. However, my project was done in the dry winter season and it has set up nicely--high and dry in the attic.


2012-10-08 12:29:14
Cellulose insulation install starts with right preparation | Greenest Insulation Blog says:

[...] to be conducted unobstructed. When the attic access is inside the house more planning is needed. See one home owner’s personal account for ideas on what to consider when doing a cellulose insulation attic [...]