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Community and Q&A

Seal Soffit Baffles

pico_project | Posted in General Questions on

Still working on our remodel. Trying to get the attic done this week so we can have it blown in with cellulose and get the heat going.

Attic floor has all be air sealed. We put long Accuvent soffit baffles in from the exterior and they need to be stapled to the roof deck from the attic/interior.

How important is it go back over these with can foam to air seal the edges? They are pretty tight in place, but obviously there will be small gaps. Our roof pitch is pretty low so it won’t be fun, haha.

Also, due to the low pitch roof the end of the baffle is about 18″ off the top of the attic floor. Will cellulose we need about 16-18″ to get R60. How far down from the top of the baffle should we bring the insulation up to?

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  1. Expert Member
    BILL WICHERS | | #1

    It's not really important to seal those vent baffles. The "sealant" is primarily used as glue here when people use things like Great Stuff to install the baffles. Tacking the baffles in place with staples works fine too. The primary purpose of those vent baffles is to keep a clear vent channel under the sheathing (i.e. to keep loose fill insulation from plugging the vent channels out at the eaves), and to prevent wind washing of the insulation on the attic floor. The very small amount of air that might leak through the edges of an unsealed vent baffle won't make any appreciable difference in the performance of the insulation on the attic floor, so it's not a big deal to diligently air seal those. I'd probably try to tack them to the back of the top plate a little, mostly so that the top plate gets covered with insulation too without flooding the soffit, but that's the only place there is really anything somewhat critical to get right with these.

    Air sealing the attic floor is different, because there it's all about stopping air leaks, not keeping an open channel for ventilation. Completely different purpose.


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