Insulating Around Direct Vent

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sirraf511

New Member
Jan 26, 2014
10
KY
We have chosen the Fireplace Xtrordinair 864HO for our new home. I am curious how to insulate the framing box for the fireplace? I have looked online, but have not found much information about how to do it. The fireplace will be placed on an exterior wall and the framing box will be built into the interior. Should I insulate the exterior wall as normal and also insulate the framing box all the way to the ceiling? Any suggestions would be greatly appreciated. If anyone has photos showing the process, that would be great. Thanks
 
Build & insulate your wall normally, but frame a small hole thru your outside wall for the wall thimble & the vent. The inside of the interior chase shouldn't need insulation, unless your installation manual dictates that is required. If you want to sheetrock the inner walls, that's up to you. It will actually result in a "stiffer" construction of the chase...
 
Thanks Daksy,

I forgot to mention that the fireplace will be vented through the roof. It is also a one story home. So you are saying to insulate the exterior wall and the interior "bump out" walls as well?
 
No. No need to insulate the interior chase walls. You may have to have a firedeck at the first ceiling level...
You may want to insulate that, or at least run some tape gasket around the venting where it passes thru the
firestop in that firedeck...
 
Firedeck? I'm not familiar with that. Would that be something the fireplace installer will put in, or would it be my framer? I've just heard stories of bad drafts coming through direct vents and was wanting to make sure I didn't have that.
 
The installation manual for that unit:

http://www.fireplacex.com/productguide/productdetail.aspx?modelsku=96900143#Documents

Page 17 cites a Vent Firestop, that is either placed on the wall or on a firedeck. A Firestop is a metal component
that fits around the vent pipe with clearance to combustibles designed into it.
A firedeck is required in framing, where a vent passes thru each floor (or ceiling).
It is designed to deter flames from passing thru one floor (or ceiling) to the next... Your builder/framer should know
what it is & where to place it.
Otherwise, talk to the salesperson at the hearthshop.
 
If u use any insulation the 100 % fireproof Roxul is the only way to go!
 
Thanks everyone for the replies and info. I'm just wanting to make sure my fireplace is not a source for drafty air and an extremely cold spot in the house. Do you recommend inuslation in the attic where the vent pipe goes through?
 
If you're going to insulate that pipe in the attic, you'll need what is called an attic insulation shield. It's basically an aluminum box that's open top & bottom & runs from the firestop to the underside of the roof sheathing, & like the firestop, it has the clearance to combustibles built in...
 
Thanks again. I'll get with the fireplace dealer and make sure everything will be used to make sure it is insulated properly.
 
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