BeGreen said:tlhfirelion said:ok so here is the pic of the area I am looking at having the pass thru to the old chase and up and out. In case you can't see the measurements they are 27" from the bottom of the header seen and the one that the roof joists r sitting on. The other one from the outside studs is 43.5". I assume I would need to remove the two inner studs in this pic to then have a combustible clearance needed assuming the thimble would remove the drywall to the proper distance???????
Slowdown and don't do more demolition work until you have downloaded and read some installation manuals for chimney flues. Also, be careful to use the right terminology because it can be confusing and misleading to just say double-wall. For simplicity sake, let's use Simpson Duravent pipe terms.
For the interior flue piping you will use DVL double wall pipe. It needs a minimum of 6" clearance to combustibles. For everything on the other side of the wall you will use class A double-wall pipe (DuraTech). This class A pipe has a minimum 2" clearance requirement. Now, for the moment lets ignore the boxed exterior chase. Assume it isn't even there. What you will be constructing is an exterior class A flue, hopefully with a clean out tee on the bottom. There will be a short horiz. class A pipe that extends from the tee, through the thimble, 6" into the room. The thimble is an adjustable bracket that maintains the 2" clearances. You shouldn't need to remove any of the existing vertical studs as long as the flue is centered on one of the existing stud spaces. If not, you will need to box it in. Does that make sense? From that stub of class A now sticking 6" into the room you will transition to the 6" double wall interior pipe for a short horizontal run, then an elbow directly over the stove flue connector and straight down to link the stove to the elbow. Try to be sure that the horiz. connecting pipe between the elbow and the thimble is pitched uphill 1/4" per foot. Smoke does not go downhill very well.
Simpson installation instructions:
http://www.duravent.com/?page=ts.php (choose from the second popup menu - DuraTech 5"-8")
Look at figure 24 on page 17 for a diagram of how the thimble works in conjunction with the clean out tee. Figure 27 is close to what your setup will look like, but you have a top vented stove so up to an elbow and then connect to that to the thimble.
rdrcr56 said:In the picture of your opening is that horizontal stud what you are talking about as 46 in. high?
rdrcr56 said:Well I guess I cant picture the framing of your wall, so what I'm trying to get across is that where the ceiling and the wall meet that is where the load bearing joist should be, you should be able to remove the wall that was above your old fireplace up to close to the ceiling.
BeGreen said:Considering that at some point in the future you might want to upgrade the stove, perhaps build it slightly oversized and over-spec? If you agree, put a layer of micore on top of the plywood, then a layer of sheetmetal, then a single top layer of durock. Screw the sandwich together per durock's recommended interval. That would give you a more future-proof hearth for just a few more bucks.
fossil said:This copied & pasted from USG:
"DUROCK Brand Cement Board has an R value of 0.26"
Rick
BeGreen said:Rick, thanks for waking me up - firelion, is this for the Century 27007 stove? I assumed you were following the manual which now that I re-read it calls for R.893 or better on the hearth. So far you have only R .52. If you go back to my original instructions you will be good to go.
Are my docs in conflict with your's?
BeGreen said:Rick, thanks for waking me up - firelion, is this for the Century 27007 stove? I assumed you were following the manual which now that I re-read it calls for R.893 or better on the hearth. So far you have only R .52. If you go back to my original instructions you will be good to go.
Are my docs in conflict with your's?
EDIT:
Argh! Documentation department please! Now I see what you are seeing too. And it says .446 for the same 3/8" millboard. So you are OK as you are following the stove specifications.
BeGreen said:No, see above post. This is a mess up with Century's documentation. You can go by the specs you have. If questioned, you have the paperwork to prove it.
fossil said:Not sure why you keep mentioning the 1" of plywood. Plywood's a combustible. All the required insulative value needs to be between the stove and the combustible. The plywood has nothing to do with the required r-value of the hearth. Just wanting to make sure I understand. The mortar buys you next to nothing, and I'm not sure what you mean by hearth stone, but if it's some sort of stone veneer, than it doesn't have much r-value either. Rick
BeGreen said:Follow your paperwork - what the exact model of your stove. The higher hearth R value is for the 27007.
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