Home>Discussions>INSULATION & HVAC>Attic Fiberglass Insulation w/ one side foil, one side paper
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Attic Fiberglass Insulation w/ one side foil, one side paper

I just moved into a new house in Massachusetts and I need to add more insulation. I'm confused by what I am looking at though and I can't seem to find a example of this on the web.

The insulation that is already there is fiberglass with a paper-covered foil facing towards the living space and some kind of coated paper facing up into the unheated attic. I was planning to just roll out some unfaced insulation on the top of it but then I got concerned about which side functions as the vapor barrier. I wouldn't be surprised to find this stuff was installed incorrectly because that would be par for the course in the new house.

If anyone can tell me if I am good to roll on the unfaced insulation as is or if I should alter what is there first I would be much obliged.

Re: Attic Fiberglass Insulation w/ one side foil, one side paper

If it were me ... I would either rip off the paper facing into the attic or cut slashes in that paper facing ...... then lay the unfaced batts over top..
Can't say I've seen what your describing and quite frankly hope I don't.

Hope this helps.:)

Re: Attic Fiberglass Insulation w/ one side foil, one side paper

Oh, I've seen it. It was also in my attic. I ran into the same issue. I talked to numerous people and no one had seen it before. It got to the point where I actually called Owens Corning and talked to one of their engineers for advice. Basically, he said the craft paper should be to the living area and the foil to the unheated. BUT, if you are to put more on top. Then all insulation would need to be scored to prevent a vapor buildup. The insulation was probably put in during the '60's or so. My decision was to remove all the old questionable insulation and start from scratch (pardon the pun). I was not going to open myself up to accidentally not scoring or missing to score and creating a bigger problem.

If you want to go the route of removing it, just let me know. That is a whole other discussion of Mr. Murphy coming to visit.

Re: Attic Fiberglass Insulation w/ one side foil, one side paper

Thanks to both of you for the feedback. Holliston is a couple of towns away and the house is from the 60's so this is making sense. When my wife gets back with the digital camera in a couple of days I'll post some pictures of the stuff for posterity on this thread in case anyone else finds the stuff in their attic.

One question though - if I keep what I have and stick more on top, did they say to score through both sides of the double-sided insulation? I would think that would defeat the purpose of the barrier, but then again, it sounds like they put it in upside down.

If you want to email how you got it all out, I would be happy to know.

Re: Attic Fiberglass Insulation w/ one side foil, one side paper

Never encountered what you describe, but.....sounds to me like it's an ill-conceived product from get-go...and is upside-down for your climate. The foil (the better vapor barrier in this instance) should face toward the living space and the paper (semi-permeable)toward the attic space.


If you poke around inside the FG...do you see any signs of mildew or simliar? (Look over high-humidity rooms like the bathroom)

Re: Attic Fiberglass Insulation w/ one side foil, one side paper

Novak, it looks like we are getting conflicting comments on which side should go down. Suffice it to say, if you want to leave it in the side to the unheated space must be scored.

From a process standpoint, my insulation was extremely old and dirty. Now, that may not be an excuse but I did not want the risk of this "dirt" to be potentially mold. Mold is a serious issue with my family due to allergies. Just didn't want to take the risk.

The removal can be somewhat tricky/frustrating, but easy. The foil and craft paper had deteriated so much it was extremely fragile. If you pulled it to hard, it would break apart.
Start to finish (new insulation), roughly 3 to 4 weekends of doing it solo. This would include vacuuming out the joist bays, you be surprised at what you find (critters).

A few things I wish I had done differently.
1) A trap at the bottom of the attic stairs. Alot easier to hose that off than trying to vacuum up insulation.
2) A cloth drop cloth for the bathroom or wherever you are going to disrobe. This way all insulation fibers and dirt are contained somewhat. Then just toss everything right in the washer.
3) Some type of pole with a 90 degree hook at the end. This way if the insulation rips where you can't reach easily. You don't strain yourself in odd positions getting it out. Big people trying to get into small places is not fun.

Those three tidbits are just things I wish I had done, but were not really major issues. Just nice to have done differently.

The one thing that I did right in the process is post removal and vacuuming. Putting in the air chutes/vents before putting in the new insulation. It was easier to stretch into the eaves without having insulation right beside your face. The airchutes I wish I could have found was shown on ATOH or TOH sometime ago. It contained angle piece to prevent you from placing the insulation to far forward. I think I did that in certain places due to ice dams last year.

Re: Attic Fiberglass Insulation w/ one side foil, one side paper

As mentioned earlier I haven't run into this type of insulation myself.
After doing some research I had found something that might be the case here.

It seems there was a type of batt insulation that had a foil face on one side which was a radiant barrier and a vapor retarder .... the other side had a kraft paper backing which was a " breather"..... designed for use in crawl spaces.

The intended method of installation was to have the foil side toward the living space with the paper side to the attic ( in this case ). The reason being ... the foil side was considered as the vapor barrier.

If that's the case here ... it would make sense to leave the insulation laying the way it is and simply cut slashes or remove the kraft paper ..... then place the unfaced over top perpendicular to the direction the existing is run.

2 cents worth.:)

Re: Attic Fiberglass Insulation w/ one side foil, one side paper

Thanks again for all of the replies. I've posted a few pictures so you can see what I am talking about. It seems to make sense that the foil side goes towards the heated space as the fiberglass is adhered to this surface. The other side seems to rip off with no problem. I think I am going to go the route of ripping of the paper side and leave the foil in place as long as there is no mold or mildew damage in what I find.

If this turns out to be the wrong choice, I'll be back to keep others from making the same mistake....

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