Attic sealing versus effective system balances

First off, I am not an Energy Auditor and don't hold those certifications or experience.  I am a realtor with 2 green designations that assist my clients, both buyers and sellers, with energy efficient upgrades.  It is my job to be able to convey my unique knowlege to help them lower their energy bills, improve indoor air quality, assist with allergens and if they care lower their carbon footprint.  

You might have seen a post that was featured about Energizing my 1979 home.  I'm still completing that process and hope to gain my NGBS certification for the home soon, when the Arizona desert climate allows a new Xeriscape project to be completed.  

That said, I am working on an odor issue that has cropped up.  

After installing Icynene in my attic, not removing the existing cellulose, I noticed an odor that kicks into high gear in mid-afternoon when the 16 SEER HVAC works diligently to cool this block constructed house.  

The energy auditing company advised I could either remove the cellulose or aeroseal the ducts.  I chose the latter solution but now wish I had removed the cellulose as the odor still exists, although much milder in nature.  

Explaining this to a friend, he advised that if I remove the cellulose won't I be acting counter-productively in allowing the heat to enter the house?  My thought is that I sealed the ducts and don't have that much heat gain in my attic.  

The friend also asked why I would choose to remove the cellulose and not replace it?    He also asked if I wouldn't be creating a pressure issue.  

I'd love some answers from a different source that my energy auditor to verify my unspoken thoughts and to get good feedback for discussion so that I can better relay the dynamics of the products I constantly discuss.  

Thank you! 

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Comment by Jan Green on September 16, 2016 at 8:44am

I did not make a choice to leave the old insulation. The subject wasn't brought up.  Yes, I'm having to spend more money because the contractor told me (remember I'm not the expert here) that I could seal the ducts or remove the old insulation, and he didn't give me any extra details.  If I had known I was still going to have an odor, I would have removed all of the old insulation.  It's only about 4" thick.  

Thank for telling me to remove the insulation - my opinion as well.  

And thank you for the tip about viewing attic re moisture.  The roof is fairly new, so hoping that any former leak has not created any additional issues.  

My home inspector has a moisture meter, so will ask a favor of him to check out the attic.  

Love the idea of an exhaust fan and will suggest this to the handyman that I hire to remove the old insulation.  Woo hoo!  Finally a step by step process that will resolve my issues.  If only the contractor had told me this!! Thanks again John!

Thanks also to Judy and William for feedback.  I appreciate your comments!

Comment by John Nicholas on September 16, 2016 at 8:06am

Jan,  You have a typical problem for everyone dealing with contractors and spending money. You made  choice to spend money to spray the roof deck and leave the old insulation. Sometimes a problem, sometimes not.  Now you get an objectionable smell. So you fix the duct leakage, spend more money. Smell is less.  OK. Now try removing the old insulation. Spend more money. 

Contractors want to work so, they quote less expense and leave optional but perhaps optimal improvements off the table.  Not a bad idea, just a little frustrating in cases where the problems continue, or others crop up.

At this point, I would remove, but not replace the cellulose. You can always spend the money to replace later. But I would not recommend that. If you need more R-Value on top, add more SPF to the roof deck.

After you get the cellulose removed, have someone, check the framing and top of the drywall (attic side) for water damage.  Stains on the drywall, black areas on wood ceiling joists (horizontal) that are not mold.  Do not use a mold remediation contractor for this inspection.  Use someone with good eyesight, a good light and a moisture meter. IR as a preliminary is OK, but the attic side must be examined and a moisture meter used. A dry stain should not cause a significant odor problem. 

Given the desert rainfall, this inspection could wait until you feel the attic has had enough air changed out to remove the odors. In my house, I would figure out how to provide a fresh air in to the attic space and a stale air out to speed this process. I would probably use an exhaust fan approach.

Comment by Judy Rachel on September 15, 2016 at 9:26pm

What does the smell, smell like?  Dead animal?  Rotten eggs?  Fishy?  . . .  When the A part & B part of Icynene are not mixed in the correct proportions the Icynene can smell bad pretty much forever after installation. 

Comment by William Collins on September 15, 2016 at 9:27am

Check the Energy Vanguard Blog as I believe that Allison Bailes just posted something about a month ago about advising that the existing cellulose should be taken out if you spray foam the roof deck.  

Comment by Jan Green on September 12, 2016 at 6:13pm

The smell was there event after cleaning ducts, so it is not in the ducts and appears to be the old cellulose.  I had an air test as I thought I might have mold, had it in a laundry room wall but General Contractor supposedly fixed so I was worried.  Clear air test.  

Thank you for your comments Eric.  It's been great even having someone to chat about it!  A meeting of the minds....

Comment by Jan Green on September 12, 2016 at 4:19pm

Thank you Eric.  I had the ducts cleaned, then sealed, AFTER icynene and new AC installed.  Thought I had this figured out.  I would crawl this attic myself, but had back surgery and can't do that physically just yet, so may have a handyman crawl the attic space to look for anything that might possibly be smelling up the attic, YUK!   The roof is realtively new (2010) so it might have had a previous leak but you'd think that would be aired out by now. Did above work in 2015 prior to moving in.  Have had the return popped up and can't figure it out.  Very frustrating after doing all of the above. 

Comment by Eric Kjelshus on September 12, 2016 at 4:03pm

If I was there 1st) is to test air CO VOC dust temp RH.  2)nd Then look for dead things  mice rats birds bugs  may have vack the duct and suck out some of inside duct sealant.   3) smell is a hard one some times to find. A teck of mine found a dead rat  in a new house and did not sell till the smell was gone.  that was in return - Pop the end cap off and smell both supply and return.    This is hard one.   4) water leaks just a very fine mist will stink up an attic cellulose   5) roof leak that drips on attic cellulose will stink up the place  

Comment by Jan Green on September 12, 2016 at 3:14pm

I'm not concerned about the insulation as much as I am the smell coming from my attic. I've already ran the insulation by the verifier in Tucson, so I'm fine with what I have installed.   If you read my post my concern is the smell. 

" The energy auditing company advised I could either remove the cellulose or aeroseal the ducts.  I chose the latter solution but now wish I had removed the cellulose as the odor still exists, although much milder in nature.  

Explaining this to a friend, he advised that if I remove the cellulose won't I be acting counter-productively in allowing the heat to enter the house?  My thought is that I sealed the ducts and don't have that much heat gain in my attic. "

I've already turned my attic into conditioned space, but I want to get rid of the smell coming from my attic.  The attic access is in my master closet, so I can smell it there the strongest, not good.   My question is if I remove the cellulose, what will that do the ventilation into my house?  I've heard that that actually helps the spray foam insulation breathe and react better.   

Comment by Bud Poll on September 12, 2016 at 1:28pm

In terms of traditional r-value Icynene is rated at r-4 per inch for open cell and r-4.9 per inch for closed cell, per their web page.

I checked InSEALator's web page and did not find a reference to r-value per inch for Icynene, but I did see some of the typical arguments for why spray foam performs better by air sealing as well as insulating.  Unfortunately, I'm not sure what your installer is referencing to say you are at r-50 or whether that will meet your requirements.  Perhaps others will comment to help with this determination. 

Not trying to throw a wrench into your project, but better to clarify now than later.


Comment by Jan Green on September 12, 2016 at 11:49am

No, as I said it's at least 4" thick and the installer, InSEALators, verified it's R50. 


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