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cbaur88 01-25-2011 03:34 PM

Insulation Installed Backwards/Advice

To tag off another thread I am in the same boat up here in S.Jersey. While putting in recessed lighting in our kitchen I noticed that our insulation looked a little thin. Doing some research on the topic I found out the batts are installed the wrong way. Between my joists I have either blown fiberglass or cellulose I am not really sure, it's only about 3 inches thick at best. Below this blown in insulation there is some sort of paper or vapor retarder laying on top of the drywall. I only noticed this in one section between the joists, I have to get back up there and confirm this is all over. Going horizontal across the joists is fiberglass batts maybe R-11 or R-13 with the paper faced up toward the sky not the warm part of the house and there are some seems between the batts that are erking me.

Had the HD come in for an estimate of just a portion of my attic space done (I have a split level home with basically two attics) at approx 600 sq feet and wanted $1,300 just to blow over top what I already had. That seems the easy way out and I thought if they were going to do that would it be ok for me to take the easy way out and just do it myself?

So I am looking for advice assuming there is some sort of barrier below the blown in insulation on what to do? What I'd really like to do is rip it all out and put the batts faced correctly between the joists and blow over top of it, but I simply know that is a monumental job and I am not up for it. Next is I can rip out the batts all together and simply blow in more fiberglass or cellulose. I do not appear to have any frost issues or moisture issues at this time. I have some sofit issues that are blocked w/ insulation but aware of them and will install some vent baffles to address. Any advice would be welcome.

I thank you in advance for your time and help. :)

P.S. My attic is COOOOOOLD, suppose to be that cold. It's "I see dead people" blowing smoke cold up there

Arthropod 01-25-2011 05:50 PM

It sounds like your vapor barrier is installed on the interior side of the insulation. If that is true, it is what you would want in your NJ climate.

pyper 01-25-2011 08:13 PM

So you have 3" blown covered by 3" batt with kraft on top?

how about flip the batts over and blow more on top?

cbaur88 01-26-2011 08:22 AM

Thanks for the posts fella's :)

Arthropod: Yes I am hoping that is the case. I only saw/checked this barrier paper in between one set of joists. I need to get back up there and confirm this is the case through most of the attic. If it is then I am thinking I am ok w/ a vapor barrier.

Pyper: Yes, I measured approx 3" of blown and approx 4" - 5" of kraft fiberglass on top for an approx total of 7" - 8". I was thinking of flipping the batts and blowing on top but I was not sure if I'd be creating some type of moisture issue between the ceiling and the kraft paper. As it would look like this: Ceiling --> Vapor barrier --> 3" blown insulation --> kraft/fiberglass batts. I don't seem to have a problem w/ moisture up there now with the batts the way they are so I am not sure if flipping would make a moisture issue. If I knew it was pretty safe to do I would certainly flip them and blow on top. Good suggestion and thanks!

Maintenance 6 01-26-2011 03:43 PM

You definitely don't want two vapor retarders in the same insulation system. And you definitely want a vapor retarder as close to the warm surface of the living space as possible. I would lift the upper batts and slash the kraft paper with a utility knife. About 3" apart. nothing fancy, just destroy the integrity of the upper vapor retarder. Then you can roll out more fiberglass or blow in whatever you want.

Gary in WA 01-26-2011 10:40 PM

Remove the second paper facing, if asphalt coated. Cutting slits would defeat it if it was an air barrier (not a vapor barrier), but the slits wouldn’t let much moisture through compared to the surface area left (still 99.9% effective); “Should the joints be taped?
Johns Manville does not recommend nor require that the joints be taped. Vapor retarders
are area weighted. The small gaps would not allow a significant amount of water vapor
through the wall, ceiling or floor.” From:

The paper will also create empty pockets that wouldn’t have material to insulate and could leave air raceways under the paper to feed convective loops;

If you blow cellulose on top to enough density and volume, you will lose any R-value the old has because of compression. If f.g. blown on top, use a density without the inherent convective loops. Leave the vapor retarder on the drywall unless the attic has not yet been air sealed, almost as important as insulation;


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