Had A Face To Face With Your Attic Insulation Lately?

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 Executive Director Dan Lea to write and edit the Greenest Insulation Blog. His office referenced in this story is in Jacksonville Florida.)


This entry was posted in Cellulose Insulation, DIY & Insulation Tips. Bookmark the permalink.
  1. 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

    • 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.

      • 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.

  2. 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.

    • 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.

  3. Pingback: Cellulose insulation install starts with right preparation | Greenest Insulation Blog

  4. Bernie Noonan says:

    November 2015
    I am the new owner of a 1200 sq. ft. raised ranch in Connecticut, built in 1978. I don’t believe that any of the air leaks have been sealed. There are 9 can lights. I have 8-9″ of fiberglass (batts and blown in). The baffles were not installed and are just laying on top of the insulation. The roof has a ridge vent. The two bathroom fans vent into the attic.
    Through the EnergizeCT program, I will have an energy audit done that includes sealing all of the air leaks in the attic,”if possible”. One contractor suggested vacuuming all of the fiberglass out of the attic and throwing it away before air sealing and spraying celluose to R-60(18″). It seems obvious that a clean attic will be easier to air seal and inspect.
    Another contractor said that he had never a request to remove insulation and did not have equipment for that.
    My questions:
    Does it make sense to remove 800 cu. ft. of fiberglass and throw it away?(I believe the batts were installed in 1978 and the loose fill added sometime in the 1990’s)

    Can the insulation be vacuumed out and re-blown in with new fiberglass or celluose?

    Does it make sense to combine the two materials?

    In venting the two bathroom fans, I have a choice of venting a few feet through the roof or running a vent 20+feet through the wall at the gable end.

    I appreciate any input you may be able to give.

    Bernie Noonan

    • CIMA Admin says:

      Great question. Unless existing insulation is damaged or contaminated with mold or pests there is usually no reason to remove it before adding additional insulation. After the problems you described are corrected cellulose (which I recommend, of course), fiber glass, or rock wool can be added to bring the attic up to recommended installed R-value. Installed R-value is often difficult to determine with great accuracy because the R-factor of fiber glass is extremely variable as a function of density. The mixing of batts and blown material – actually a good installation technique – complicates the matter in your case. Taking a conservative approach you might use 2.5 to 2.7 as an average R-factor then multiply this by the number of inches currently installed to calculate the existing R-value. Add sufficient insulation to bring the total R-value to R-49. The coverage chart will have R-value rows ranging from R-13 to R-60. To allow for compression of existing insulation follow the bag count and installed inches information one row higher than your calculation indicates you need to reach R-49.

      Thanks for following the Greenest Insulation Blog!

  5. daniel says:

    Blown insulation also very good which fill out all place without any gap.

  6. Chuck Mucciolo says:

    A few years ago I found that my attic insulation was sliding off the attic hatch (scuttle hole) as I lowered it into place and that insulation debris and dust were falling into the conditioned space. I set up a video camera and found the insulation was getting stuck on the surrounding frame of the opening. This is because insulation is wider than the opening so there is no way for it to fall into place without help. Gluing or stapling doesn’t work – I tried it -because the insulation just pulls apart when the hatch is lowered. I came up with a product that solves this problem and it’s now available. Please go to Scuttlebuddy.com and look at the video. It’s an easy, inexpensive and effective way to insulate your attic hatch.

  7. Gregory Willard says:

    We have been inspecting our attic lately, and we probably need to get the insulation redone. I had no idea that you should fix any problems before they do the insulation. I always thought that they would fix it for you before they sprayed. Thanks for the information. http://www.allweathershieldpa.com/services.html

  8. James says:

    My HVAC system is in the attic and I would like to blow cellulose in. Should I be concerned about the dust getting into my HVAC system? Could blown insulation do damage to the system?

    • CIMA Admin says:

      James, we appreciate for your interest in cellulose insulation. In response to your question: All fiber insulation – fiber glass, rock wool, or cellulose – has a certain amount of dust. If HVAC equipment or ducts located in the same space as insulation are not adequately sealed that dust can enter the equipment or distribution system. That is especially true with return air ducts. Since they operate at negative pressure, dust can literally be sucked into the system. Only a professional inspector could determine if that is a possibility in your specific case. You can find more about preparing for an insulation installation here on the Greenest Insulation Blog.


  9. Alicia Byrne says:

    Thank you for pointing out that we can measure the insulation level in our house using an Rvalue. I like your suggestion of using blown-in insulation to provide better coverage for your attic. My husband is thinking of having our attic insulated because we haven’t done so since we moved in 8 years ago. I will let him know about blown-in insulation as an option for our house.

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