# Is this fiberglass insulation safe (touching heating duct)?



## AGWhitehouse

No fire hazard there. Looks well sealed, so no fiber blowing there.

Just make sure you insulated the back side of the elbow so you don't permit condensation within the duct. Since you've sealed off the warm air entering that void you now have an un-insulated duct traveling through a cold space. The warm, moist air within the duct will come in contact with the cold duct wall and potentially condense. Ensuring the entire bay is filled with insulation will help to avoid this condensation.


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## nutlog

Great, thanks. 

It should be pretty well insulated all the way around the duct. I was a little worried about the heat and the kraft paper before I put the ceiling panels back up, but if we're all good here then it looks like I can finally finish up this room.


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## Maintenance 6

You are not heating that duct to anywhere near the ignition temperature for paper.


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## HomeSealed

I agree with the others.. Insulate/seal that duct from the cold as best you can, then button it up.:thumbsup:


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## Yoyizit

If the duct is getting that hot you have bigger problems.
http://www.tcforensic.com.au/docs/article10.html


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## Gary in WA

The cantilevered joists over the exterior wall are under-insulated if that one piece of fiberglass batt (in each cavity) is blocking air movement over the wall and there is no more insulation behind them. The outside joists should be insulated with cavity insulation, and foamboard (then plywood/siding) to stop the thermal radiation to the ground outside; http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces/
First add foamboard at the cantilever rim joist as solid wood is only R-1.25 per inch......

The room ceiling joists should have been covered with drywall, then your existing drop ceiling, due to the open "V"'s between the vertical ship-lap siding wall application (behind the ceiling grid end rail on the wall). These open raceways will spread a room fire to anywhere the joist travels above, very effectively. 1/4" wood paneling is fine, though because of the moisture coming through the cantilever area, the panels appear bowing; http://publicecodes.citation.com/icod/irc/2009/icod_irc_2009_7_sec002_par017.htm
That wood burns very fast due to the poly finish on it.

Gary


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## KayEmm

Hello. We recently took down a piece of drywall in our laundry room, and discovered that the precious owner had put in fiberglass with Kraft paper right up next to our heat vents. The paper side is what is next to the vents, and it was warm to the touch (the heat was on at this time.) can the vents get hot enough to cause the paper to catch fire? Our basement is finished and I’m worried they stuff the insulation all over in the ceiling of the basement. It is covered in drywall so there is no way to check without it being a financial burden. Thank you.


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