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A Hard Lesson Learned About Cellulose Insulation Installation

By Caren Rose

Elvis Presley sang, “Wise men say… only fools rush in”. Well, I rushed in to get my attic insulated. Below is my story, and at the end are 10 great tips that I learned the hard way about insulation installation.


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I had a few extra dollars and decided to upgrade my home with cellulose attic insulation. I called a licensed company that had 43 pretty good reviews on Yelp (how could I go wrong?) to come over and give me a quote. Surprisingly, the company came prepared to put the insulation in – workers, equipment, insulation, and all. They said my attic looked good to blow insulation in today – right over everything else on my attic floor – including rat feces, old insulation, old debris, and 50 years of dust.  I repeatedly asked them if that was ok, and they assured me that it was. 

Cellulose insulation is comprised of loose-fill shredded paper that is usually treated with various chemicals to help prevent rodents, mold, and fire. The installer I hired said what he was using was non-toxic, and he would cut down on dust by misting it with water during install. It all sounded great to me. The installers were in and out in an hour, and I had 10 inches of blown-in cellulose insulation in my attic. Lucky me, so I thought. 

After they left, there was a strong smell in the house. I could even smell it when I stepped outside my house.  They said it would go away in a day, 2 days tops. A few days later, it still smelled, so I called and he said it will go away in a week at the longest. He continued to assure me that what I was breathing was non-toxic and not to worry. 

About a week into living with a dead fish smell on a daily basis, I became sick. As the smell continued, so did my phone calls to the installer. He became annoyed and said my house probably has air leaks from the attic into the house. Air Leaks? What was that, and why is he telling me this weeks after he installed?

As time went on, I was getting sicker – my symptoms included shortness of breath, chest pain, and asthma.  The smell lasted for over 5 weeks. I was so sick, I could no longer go into work. I knew there was something wrong. I moved out of my house after about 7 weeks to see if I would get better, and that is when I started to do intense sleuth work on the Internet to figure out what might be going on. 

I ended up calling the manufacturer of the cellulose insulation and explained what was going on. They explained to me that the particular insulation I had should not have been misted with water and that it was probably offgassing ammonium sulfate, by the description of the smell.  They led me to their Material Safety Data Sheet (MSDS), which tells about the chemicals in the insulation. By wetting the product, I believe this installer put my health in jeopardy. Ammonium sulfate is an upper respiratory irritant. Not knowing any of this at the time, and being repeatedly told that it was non-toxic and would go away, was not a good recipe.

So, do I really know what went wrong with my installation? I disputed my credit card charge to the installer, which prompted a phone call from him. The installer said he might have gotten a bad batch from the manufacturer and is now using another manufacturer as he was getting complaints. He somewhat ignored that I told him the label said “Dry install only” and said they mist that kind all the time. He said that in the future he would pay much more attention to someone calling and complaining. So was it a bad batch? Perhaps it was over misted more than his other installs? In either case, it was definitely installed improperly and I do feel that it was off gassing ammonium sulfate and that is not healthy at all. 

In this unfortunate journey, I have learned a lot about cellulose insulation and insulation installers. Here are some tips and precautions that should be taken:


  1. Before even calling any insulation companies, have your attic checked by an HVAC professional for loose, torn, damaged, or old air ducts. Have them repaired or replaced if needed. Check for air leaks from the attic to the inside of your house. These might be around the air duct registers, the furnace, the place where your bathroom and kitchen exhaust pipes meet the attic, and where electrical and plumbing meet the attic. If you have an attached garage, make sure it is sealed off from your attic.  If your attic access is in the house, make sure it is tightly sealed with weather stripping as well. Also, have them remove any rodent droppings and seal any entryways where rodents can access your house or walls.
  2. Don't depend on your insulation installer to do what is right for you and keep you safe: remember they are a business and are out to make money.
  3. Get the manufacturer’s name and the code number of the insulation to be installed.  Go to the manufacturer's website and look at the MSDS and the FACT sheet for the product code. The MSDS will tell you about the chemicals used in treating the insulation, and how to protect yourself from acute hazards. The FACT sheet should provide other information including how it should be installed. 
  4. Have your potential insulation installer give you a cellulose sample in a baggie and take a whiff: it should be odorless. It might smell like newspaper a bit because that is what it is. Sit with the sample for a day or two and see if the smell bothers you, and if it goes away. Not all cellulose insulation is the same; some may be treated with different chemicals and some may only be treated with borate. Some can be installed wet and some only dry.
  5. Make sure the company you hire is installing your insulation per the FACT sheet. If it says “dry install only”– do not hire them if they are installing it wet. Even if they tell you it is harmless and they do it that way ALL the time – run don’t walk to another installer.
  6. If you are going to use blown-in cellulose insulation, know that it is dusty. Anytime anyone goes up into your attic, there will be insulation on them and pieces coming out into your house from the attic entry point.
  7. Also be aware that properly installed insulation should not cover your recessed lights, furnace or electrical areas to prevent fires. Your attic soffit vents and gables should not be covered so there is ventilation. A good idea after your attic has been insulated is to have them take clear photos of every area, go up and look for yourself, or hire someone from another insulation company to check the job. It may cost you a house call fee, but it is worth it. 
  8. They may say it is "fine" for you to stay in the house while they are insulating, but I would say, "go outside". Why risk it? Take your kids and animals outside. Or put your animals in a room with the windows open if you can't take them with you. After they are done insulating, keep the windows/doors open for a couple of days to air out. You may also want to have someone take a look in the attic and make sure the installers did not loosen your air ducts from walking up there.
  9. The most important tip I can provide for you is that if you smell a chemical smell that does not go away after a day or so, get the insulation removed or call an environmental inspector to determine what the smell is. If you get the insulation removed, have it done safely by a company that will seal up your air duct registers, recessed lights, and exhaust fans and create an enclosed exit when removing so the cellulose dust does not enter your house.
  10. The final tip is: don’t be in a hurry. Do your research and be safe.

Whoever thought getting insulation was so complicated? It is a shame that we have to do all this careful investigation, but take it from me, it is worth it: it can save your health, your family, and your wallet. Happy home improvement.



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A Hard Lesson Learned About Cellulose Insulation Installation:  Created on June 14th, 2014.  Last Modified on June 14th, 2014


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