In the process of installing new pipe for my new stove and am switching everything from 8" to 6". I am wondering if theres a way i can get away with using the same 8" roof boot so i dont have to get into the shingles. Has anyone had any success doing this?
6" pipe in a 8" roof boot?
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You'll want to use a proper flashing sized for the chimney. There may be an option and that is to use triple wall DuraPlus chimney which is 10" OD and should fit the 8" flashing. DuraPlus is the value line of DuraVent chimney sold by Home Depot and Northline Express.
maple1
Minister of Fire
What exactly do you have for chimney now? Couldn't it stay in place, and you transition from 6" to 8" where pipe meets chimney? What is driving a chimney change?
The chimney is older from the 80's. And i was told that go 6" to 8" is a little to much to increase and im really not sure how well this old system was installed as the stobe and pipe clearances were way off. And wouldnt the draft be better for an epa stove a full 6" chimney
maple1
Minister of Fire
A lot of that likely depends on exactly what you have for a chimney (e.g. height, outside clearances etc. - how well it does or doesn't draft) & stove. And pipe configuration in between.
You are right at that age i would replace it to. The new stove will work much better on a 6" chimney. Not to mention by code you cant go from 6 to 8.
With the short chimney I would stick with 6". However going from 6-8" is is pretty common.
bholler, what code is this and what is the intent behind such code? Is it ok if stove manuals that say it's ok.
Code says you cant change the size of the pipe more than 1" from the collar on the appliance. And yes if the manufacturer says its ok in the manual it is fine. The intent is to make sure people are using appropriatly sized chimneys for their appliances. I dont know the code number off hand but it is in irc.
We’ll sure, if the 8” is not usable for some reason then you can replace it with new 8” and avoid all of the problems with downsizing to 6”.
There are some nice 8” stoves.
What problems? We do it all the time its no big deal. The hole for the new 8" is rarley the same size as the old anyway. And i would never recomend hooking a new appliance to a 30 year old class a. They typically are only expected to last 25 years. Plus 8" stoves are huge expensive and you have very few choices.
Or buy one of the many 6” stoves that allows connection to the new 8” pipe. My very inexpensive, and good nc30 allows this. Does anybody have a 6” stove that can’t be vented into an 8” chimney?
I can see why he wants to avoid messing with the roof flashing. So many roofers seem to snot the whole thing up with tar and by going smaller he may need new roofing that won’t match.
I can see why he wants to avoid messing with the roof flashing. So many roofers seem to snot the whole thing up with tar and by going smaller he may need new roofing that won’t match.
Yes most do not allow it. The 30 dumps enough heat up the stack it can work fine on 8" many others give you allot more control and wont work as well on 8".
And they make flashing w ith oversized bases for this exact situation. Regardless do you really want to rely on a 30 year old peice of flashing anyway?
Oh and page 4vof the nc30 is an entire page titled why the correct flue size is important : 6". So they may allow it but they recomend against going larger than 6"
No reason to goop a flashing all up. There should be no tar showing.
What if you install the new 6" stove using the old 8" and it does not function up to par late this fall? Terrible time of the year to replace the old 8" and roofing parts. I'd just get it over with. Eliminate that potential headache now while the season is correct. Just my opinion. Good luck.
![[Hearth.com] 6" pipe in a 8" roof boot?](/talk/data/attachments/227/227169-a5266145e5d779706fa5bc599b9ed731.jpg?hash=1-Wkh2bXdq)
![[Hearth.com] 6" pipe in a 8" roof boot?](/talk/data/attachments/227/227170-851a94eb8c32ebe4c4e52c737a6d4b6b.jpg?hash=arc8vtF8I3)
It also says on page 5 -
"The area of the chimney liner must also be equal to or greater than the area of the flue collar on the stove. If the area of the flue is greater than the collar, it should never be more than two and 1/2 (2.5) times greater."
"The area of the chimney liner must also be equal to or greater than the area of the flue collar on the stove. If the area of the flue is greater than the collar, it should never be more than two and 1/2 (2.5) times greater."
Thanks guys for all the replys, i will be replacing the 8" boot. Tearing shingles up dont bother me, did it for years as a carpenter.
Good deal. That will allow the installation of high quality chimney pipe and have the optimal venting for the stove.
So i thought i had settled on replacing the boot but had another idea lol what if i drop the 6" pipe through the 8" boot and use one of the chimney pipe support brackets to keep the chimmey in place? I beleive there is a code that if the chimney is a certain heighy you must use one any way correct?
maple1
Minister of Fire
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