Finishing material for the inside of a chase

[JEEPSTER 401]

I am working on putting in my new fireplace and am wondering how to finish off the inside of my chase. The entire chase is going to be insulated and my questions is what material to cover the insulation with on the inside. I was thinking either drywall or cement board. What are everyone's suggestions.

Thanks in advance

 

[DAKSY]

What kind of fireplace?
Is it a ZC "heat vacuum", or an EPA compliant unit?
For most of them, you can use 1/2"ordinary sheetrock, but I've
seen some building inspectors require 5/8" heat resistant stuff.
Your install manual is the Bible on the install, with the local codes
superseding that...
We install them with 1/2" sheetrock. but only up to about 8 foot high
in the chase, & the sheetrock is in there primarily to contain the insulation.
We also use caulk to seal any seams in the sheetrock to prevent any cold air penetration.
At the 8' level we run horizontal a deck of sheetrock with insulation batts laid over it,
maintaining the required 2" clearance to the vent stack.
We use aluminum tape to seal both the firestop to the deck & the vent to the firestop.
We run the 4" aluminum vent off the Chimney Air Kit (CAK) up thru the deck to
the cavity above it.
HTH

 

[JEEPSTER 401]

The fireplace is a Lennox Montecedo. The manual states either drywall or sheet rock. I will have to check with the local building code. Like you said all that this layer will do is to hold the insulation back. So the at the 8' high mark you basically box it off with the 2' clearance around the stack? I may have to go a little higher than that because I am ducting a heat run through the chase into the kitchen upstairs and I would like all of that ducting to be in the insulated area. Now above the 8' mark do you still use insulation without any sort of material covering it, like just plain old paper faced batting? Thanks for the help.

 

[MountainStoveGuy]

dont fire stops have to be installed every 8'?

 

[JEEPSTER 401]

dont fire stops have to be installed every 8'?

I do believe, That is what I am planning on. One at the basement ceiling or a little higher and one at the attic. I am just wondering if I should keep going with the sheetrock all of the way up the 24' chase, I think that is what I am going to do???? Suggestions?

 

[jtp10181]

Just use drywall, don't waste money on durock. This is all going to be hidden in the chase, correct?

Make the joints tight and seal them with caulk. At the 8' mark for the draft stop you should use an approved metal firestop for the vent system you are installing. Caulk if allowed. Use an attic insulation shield and insulate the first draft stop like an attic. The rest of the way up you could just insulate the wall between the house and the chase, leaving the chase outside the envelope of the house. For a warmer flue you could insulate and drywall the chase all the way up to the attic, bringing it inside the envelope of the house. If you do then then save the attic insulation shield and draft stop insulation for the attic.

 

[JEEPSTER 401]

Yep all of it will be hidden inside of the chase. So you guys just caulk the sheetrock joints and don't finish them off with tape and mud?

 

[jtp10181]

why waste the time with tape and mud? Caulk seals it just as good, and they already use caulk for wall and roof penetrations. For big gaps sometimes they use whatever tape is handy, tyvek or foil tape.

 

[JEEPSTER 401]

Is there a certain type of caulk that I should use? The caulk does seem much less time consuming, I think that I will go that route.

 

[jtp10181]

For cheap stuff, we just use cheap latex painters caulk. Anything near the pipe that would get hot should be silicone caulk. Most wood pipe systems do NOT allow you to caulk the fire stops.

 

[daryl]

[quote author="MountainStoveGuy" date="1253612995"]dont fire stops have to be installed every 8'?[/quote



Most chimney installation manuals say every 8' or floor / ceiling penatration.