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Old kraft paper turned black over time. Is this normal?

Old kraft paper turned black over time. Is this normal?


  #1  
Old 08-28-15, 05:29 PM
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Old kraft paper turned black over time. Is this normal?

I have a house that was built in 1980. The basement was unfinished when built but was mostly finished by the previous owner. I think the insulation in the floor joist is mostly original. My problem/question is that this old kraft faced insulation has turned black all or in part. I live in a dry climate (Utah) and there has never been any water damage as far as I can tell. It doesn't seem to be around any ducting either. I am working on finishing this room and I wonder if this is something I should worry about? Should I rip it out and replace or just remove and leave un-insulated. I have read in places on the net that you should not insulate your basement ceiling. I've also heard otherwise so I am not sure what to do. Any help is appreciated. I have attached a link to some pics of the insulation. Let me know if the the link dont work.

https://drive.google.com/folderview?...E0&usp=sharing
 
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Old 08-28-15, 05:37 PM
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Welcome to the forums.

Usually the paper turns brown/black from dirt passing by it and getting stuck to it. Usually you'll see that in the walls and in the ceiling near the walls where the air is drawn thru the walls into the attic.

If you have an oil burner.... that will accelerate the process.
 
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Old 08-28-15, 05:47 PM
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I'm not sure it's dirt. It does not rub off and as you can see in the pictures, one bat may be black and the adjacent is not. Also this particular room has no air vents in it and the door is always closed. Not sure if this matters. I guess my biggest worry is that it is mold. Not sure why it would be but I'm also not sure why it would turn black unless the paper is treated with something.
 
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Old 08-28-15, 05:56 PM
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How about an oil burner ?
 
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Old 08-28-15, 06:09 PM
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No no oil burner. The house has central air. It does have a wood burning stove in a different room in the basement but it is at the other end of the house and this rooms door is always closed.
 
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Old 08-28-15, 06:32 PM
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Basement insulation in an unheated/unfinished basement should not have the kraft facing toward the basement space, it should be toward the warm side, which is the bottom of the floor above. (basements are always cooler than the upstairs) People do it that way for ease of installation since you can staple it up that way, but its backwards.

Don't know if that has anything to do with the black paper, but I doubt there is anything wrong with the insulation itself, per se. It may just be the asphalt backing on the back side of the kraft paper finally seeping into the facing. What's most dangerous is having a flammable surface like that exposed. (see R501.3)
 
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Old 08-28-15, 06:37 PM
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Just a guess here, but the Kraft paper gets its vapor barrier properties from a tar like coating on the fiberglass side. It looks to me like that tar is soaking through over time. The lack of moisture, the inconsistent pattern (on some but not others), would not suggest mold.

As for insulating a basement ceiling, most will do that if the basement is not heated or at least partially heated, or for sound reduction, it helps a little.

As for finishing a basement, they can be tricky, but moisture is the primary issue. I'll add a link on basements.
Understanding Basements | Building Science Corporation

Bud
 
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Old 08-28-15, 08:03 PM
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Thank both of you for your help. Good to know that's it's not likely mold. I'll take a look at that link as well. Thanks. So being that the insulation is stapled in backwards do I need to fix it, replace it, or not worry about it?
 
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Old 08-28-15, 08:10 PM
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No mold, no problem.............................
 
 

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