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In attics with no soffits (or vents) can the added insulation touch the roof sheathing?

I have an older 1950's brick home with loose cellulose (I think) insulation in the attic between the rafters.  It is only a couple of inches thick with no vapor barrier.  Plan is the used rolled unfaced fiberglass between the rafters laid on top of the cellulose to bring it level with the wood (probably 3 /12" rolled).  Then roll out perpendicular unfaced 9/12 in fiberglass. The house has no soffits or vents. Do I need to use the foam barriers normally used for soffit vents to keep the added insulation from touching the roof sheathing? Especially if we decide to blow it in?

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Posted 2013-08-30T16:08:04+0000  by rcm000 rcm000

Hello rcm000.  Welcome to the Community!


In short, no.

The foam "barriers" actually serve as tunnels to allow air venting up from the soffit to pass through the insulation level unobstructed and eventually out whatever high level vents are available.  Since you have no soffit vents the only reason to put the foam liners in would be in preparation to install soffit vents.


That's one problem.  Having no attic venting makes what insulation you do have work a lot harder.  If there is any way you can vent the attic I suggest you do so.  Another issue is the lack of a vapor barrier, but as you say you are not sure about that.  There could be plastic sheeting, or maybe not.


The last question I have is your use of the word "rafters".  Do you mean ceiling joists.  I assume that what insulation you have is just above the ceiling in the attic, not up in the roof rafters.





Posted 2013-09-03T20:05:26+0000  by Chris_HD_CHI

Thank you for the reply.  The only venting are two end gable vents and 6 or so cap vents along ridge.  There is no vapor barrier under the existing insulation.  You are correct.  I meant ceiling joists, not roof rafters. So the insulating touching the underside of the roof in this case is ok?

Posted 2013-09-03T20:20:23+0000  by rcm000

Yes, it's ok.


Good news that your attic is vented, just not through the soffits.





Posted 2013-09-03T20:25:15+0000  by Chris_HD_CHI
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