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Does it Make Sense for me to Remove and Replace this Insulation?

user987's Avatar

Join Date: Jun 2012
Posts: 299

06-29-12, 11:38 AM   #1  
Does it Make Sense for me to Remove and Replace this Insulation?


I am trying to determine whether it makes sense for me to remove and replace the insulation that you can see in the attached photos. This is my garage. The room behind the garage wall is the kitchen.

The insulation in the wall is original blown in insulation. I think the house was built in the 60s. The insulation is then covered with that black Celotex material.

Do you think I could improve energy efficiency and reduce drafts if I pull out the old blown in insulation and add new insulation? Can I just stuff more insulation into the wall on top of the blown in insulation? Doesn't that bring down the r value though? I have some left over r19 and I think r30 (or close to it) from other projects.

Whether I replace the insulation or leave what is there alone, should I cover the wall with Tyvec? Will the Tyvec help to prevent drafts and increase the insulating effect on the inside of the house?

One other practical question, if the wall you are filling with insulation has wires or an electrical box, etc, are there any special precautions to take when installing the insulation?

The wall is about 8 feet high by 10 feet long. At the end of this space is an exterior door that goes between the kitchen and the garage.

Thank you for your advice.

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Northern Mike's Avatar

Join Date: Jan 2012
Posts: 2,541

06-29-12, 12:01 PM   #2  
It's hard to say how old the insulation is by it's color as they still make brown insulation.
That being said, if you have a cold/draft issue, for sure vapor barrier and new stuff (removing the old). If you compress insulation into a space it doesn't fit, you lose it's insulation value.

chandler's Avatar
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06-29-12, 04:49 PM   #3  
This was blown in from the top via holes. Note the holes for the nozzle at the midpoint? I would not remove it, but you may want to enhance it by adding to it since it may have settled over the years. If you do replace it with Roxul or fiberglas, you will need to remove all the celotex and start over, so it's a toss up. Cover the areas you have cut out so the insulation won't fall out any more.

drooplug's Avatar

Join Date: Aug 2009
Posts: 4,940

06-30-12, 06:14 PM   #4  
A wall between the garage and living space should be sealed tight as to not allow any exhaust fumes from getting into the home. It should also have 5/8" fire rate drywall on it. My suggestion is to put a 2" layer of rigid XPS over what you have. Actually, two layers of 1 inch with staggered seams would really help seal the wall. Then install 5/8" drywall over that. If the wall board doesn't go all the way to the floor, make sure you return it back to the wall to cover the any exposed edges of XPS for fire protection. The 2" of XPS will give you better air sealing, increased R-value, and a vapor retarder. And you don't have to mess around will removing the old stuff.

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