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Community and Q&A

Proper Installation of Eave Baffles

jstover684 | Posted in General Questions on

Hello All,

My name is Jeremy.  I’m new to this website/forum.  I’ve been in the residential design industry for 14 years now, and I’m getting into green building/energy efficient building more with each passing year.

Question for all of you.  I’ve tried researching this a bit online, without a clear answer.  And I’m asking as a homeowner, not as a designer (though I’m sure this will have ramifications for my work as well).  

I live in a house in Southern Maryland, and the house was built in 1968.  It’s a tri-level house, and it’s not terribly energy efficient.  The attic had 6″ of insulation in it until a week ago.  I just hired a company to bring me up to R-49 with blown cellulose (they put wet-spray in to 18″ to account for settling).  They also air-sealed everything and put in a panasonic whisper bath fan for indoor air quality.  

They also did baffles between every rafter down at the eaves.  This is where my question comes in.  The baffles they had were foam, and they were 24″ wide baffles.  They cut them in half (perforated I believe) and stuck them in my cavities.  However, my rafters are 16″ o.c…so the baffles don’t take up the entire cavity.  I was pretty sure that the baffles really need to be extending from inside-of-rafter to inside-of-rafter.  Am I wrong on that?  Will this cause problems (moisture, lack of ventilation – even though there was no baffles at all before last week, etc?)

Thanks for your thoughts in advance!

Looking forward to participating on the forum.


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  1. user-5946022 | | #1

    The baffles allow air from your soffit vents to get to your attic.
    You can do a calculation to determine if you have sufficient air space, but I suspect you do.
    It sounds like they either got a good deal on 24" wide baffles, just picked up the wrong ones that morning, or ran out of the proper width for 16" oc. Building materials need to be installed in accordance with manufacturer's recommendations in order to be code compliant. You might find that if you search the mfg of those baffles, that your installation is not recommended and thus not code compliant, and you may be able to get your insulation contractor to fix it on that basis.

  2. Expert Member


    As long as the baffles are large enough to provide the required total intake volume, you are fine. The small areas where the sheathing is in contact with the insulation will dry by diffusion.

  3. jstover684 | | #3

    OK sounds great - thanks guys! I appreciate the feedback!

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