Picked up 18' of stainless class A chimney pipe for $100. Run all the way?

[Bummer]

Hi,

I'm currently getting all the pieces together for a new stove/chimney install in the house we bought last year and I just picked up 18' of stainless class A chimney pipe (6") on craigslist for $100. That's obviously a killer price so I am now considering running that stuff all the way from the stove through the ceiling and above the roof. I did a little bit of reading on these forums and learned a lot but still have a few questions.

First some background on my install: I'm installing the stove in the living room where we have vaulted ceilings (11' from floor to ceiling). We have a metal roof and I would have to run the chimney about 4' out of the roof (to meet the 2' clearance in a 10' radius code). Technically i have enough class A pipe to run the chimney all the way! The stove I bought (1982 BK Pricess PT-202) is an older pre-EPA stove with an 8" flue which I am planning on reducing to 6". The previous owner of the stove had done the same thing plus I figure that the class A pipe will keep the chimney hot and draft high, especially considering the length of the stack.

Here are my questions:
- Is it a bad idea to reduce the flue from 8" to 6" considering I run a long stack of class A straight through the ceiling/roof?
- What piece do I need to buy to reduce the flue from 8" to 6" class A chimney pipe?
- Do I need a ceiling support box or can I just run the class A through the ceiling a brace it to the ceiling rafters while maintaining the 2" clearances? I have two brackets that are meant for screwing to rafters.

Thanks everyone for your help!
Chris

 

[kennyp2339]

You will need a ceiling support box, the box keeps the pipe centered so you can maintain the proper clearance of 2" around, there is also a little lip adapter in the support box that allows for air flow into the double wall chimney keeping it cool, also acts as your "fire stop" when transitioning between floors - needed is your going through the living room ceiling, then attic space then physically through the roof shingles. It also supports the class chimney weight when properly installed.
It also provides imo a nice transition from the black pipe to the class a chimney (your not seeing the stainless steel part from the living space)

 

[kennyp2339]

 

[bholler]

Well for starters no you shouldn't reduce from 8 to 6. Infact it is against code. It may or may not work just because it worked in the previous owners house does no mean it will in yours. But since you have the pipe and got it for so cheap you might as well try it. If it doesnt work you could alway switch out either the stove or the chimney. And yes you need the support box and any other components applicable.

 

[bholler]

And you will have to reduce with regular stove pipe they dont make class a reducers

 

[Bummer]

Thanks for the replies, guys! I'm going to the depot to check out the parts I still need to buy. Hopefully I can run class A all the way. It seems like there is sort of a consensus that it's not a bad idea. The reducer is a different story but I saved more on the chimney parts than the old stove I have is worth so if there are draft issues I can always scrap that stove and get a more modern 6" stove. I'll keep this forum posted!

 

[bholler]

Thanks for the replies, guys! I'm going to the depot to check out the parts I still need to buy. Hopefully I can run class A all the way. It seems like there is sort of a consensus that it's not a bad idea. The reducer is a different story but I saved more on the chimney parts than the old stove I have is worth so if there are draft issues I can always scrap that stove and get a more modern 6" stove. I'll keep this forum posted!

That sounds like a decent plan

 

[WoodyIsGoody]

Well for starters no you shouldn't reduce from 8 to 6. Infact it is against code. It may or may not work just because it worked in the previous owners house does no mean it will in yours. But since you have the pipe and got it for so cheap you might as well try it. If it doesnt work you could alway switch out either the stove or the chimney. And yes you need the support box and any other components applicable.

What will support the weight of the class A pipe between the ceiling support box and the stove?

Personally, I think going from 8" to 6" flue might even be better as long as it's a straight run. But I don't like the idea of having class A all the way to the stove. I don't know what the support requirements are for class A pipe but I would be surprised if it's rated to span the up to 8' from stove to ceiling without additional support. It might require bolting the stove to the floor since, without that, the stove is not a fixed object. One concern is earthquake. Class A pipe is heavy and Montana is in earthquake country. It would be terrible to come home to find the structure withstood the earthquake but burned down because the flue didn't.

 

[begreen]

I'm not following how one would attach class A pipe to the bottom of a ceiling support box. They are not designed for this. It seems like it would be better using a roof-support bracket and then a firestop barrier with an attic insulation shield at the ceiling for the pipe to pass through, maintaining clearances. Not sure if Home Depot would have the roof support bracket.

@Bummer do you know the brand of chimney pipe?

 

[bholler]

What will support the weight of the class A pipe between the ceiling support box and the stove?

Personally, I think going from 8" to 6" flue might even be better as long as it's a straight run. But I don't like the idea of having class A all the way to the stove. I don't know what the support requirements are for class A pipe but I would be surprised if it's rated to span the up to 8' from stove to ceiling without additional support. It might require bolting the stove to the floor since, without that, the stove is not a fixed object. One concern is earthquake. Class A pipe is heavy and Montana is in earthquake country. It would be terrible to come home to find the structure withstood the earthquake but burned down because the flue didn't.

There are support boxes and clamps made for this application that allow the chimney to pass through and be supported by a clamp.

 

[begreen]

There are support boxes and clamps made for this application that allow the chimney to pass through and be supported by a clamp.

Good to know, I haven't seen one before. Who makes them? Can you provide a link?

 

[WoodyIsGoody]

There are support boxes and clamps made for this application that allow the chimney to pass through and be supported by a clamp.

My concern was with the mass of the pipe below the ceiling.

 

[Bummer]

I haven't had a chance to go to the fireplace depot yet but am glad to hear there are pass-through ceiling support boxes. That's pretty much what I was hoping to find. I thinking bolting the stove to the floor is a great idea, and I might even add another bracket to the wall at the mid-way point.

The make of the class A i have is DuraVent. I attached a picture of the label of one of the 18" pieces:

 

[Bummer]

Another option to consider would be selling the left over class A pieces at a more reasonable price, and using the proceeds to pick up some cheaper double wall black stove pipe ))

 

[WoodyIsGoody]

I thinking bolting the stove to the floor is a great idea, and I might even add another bracket to the wall at the mid-way point.

Adding an in-room bracket mid-way would take care of my primary concern. Assuming a bracket with suitable "standoff" distance is even available.

You are the one that would need to live with the aesthetics. I know I wouldn't like it. I do like your idea to sell off/trade the extra class A for double wall stove pipe!

 

[Bummer]

Sorry for spamming the thread! I just discovered the DuraVent Brochure online:
(broken link removed to http://www.duravent.com/docs/product/l931_dt_w.pdf)

The diagram for the cathedral ceiling in particular caught my attention. I attached a screenshot of the diagram. It uses this bracket instead of a ceiling support box:
(broken link removed to http://www.woodlanddirect.com/6-inch-DuraTech-Roof-Support)

Also in the diagram the class A extends into the room below the ceiling anyway so I might just run the chimney a little farther down to the reducer....

 

[begreen]

Another option to consider would be selling the left over class A pieces at a more reasonable price, and using the proceeds to pick up some cheaper double wall black stove pipe ))

Not only would that be more practical it would also look better imo.

 

[begreen]

Sorry for spamming the thread! I just discovered the DuraVent Brochure online:
(broken link removed to http://www.duravent.com/docs/product/l931_dt_w.pdf)

The diagram for the cathedral ceiling in particular caught my attention. I attached a screenshot of the diagram. It uses this bracket instead of a ceiling support box:
(broken link removed to http://www.woodlanddirect.com/6-inch-DuraTech-Roof-Support)

Also in the diagram the class A extends into the room below the ceiling anyway so I might just run the chimney a little farther down to the reducer....

Not sure if you would want or need a cathedral support box unless the ceiling is the underside of the roof. The DuraTech roof support is what I was referring to earlier, though I like the idea of using a support box and then stove pipe better. You should be able to sell the unused chimney pipe for a good price.

 

[Bummer]

Not sure if you would want or need a cathedral support box unless the ceiling is the underside of the roof. The DuraTech roof support is what I was referring to earlier, though I like the idea of using a support box and then stove pipe better. You should be able to sell the unused chimney pipe for a good price.

I will have to price out the different options. I think I could sell the class A sections for a third of retail. I like the simple installation of the pass-thru chimney but see its downsides. Yes, the cathedral ceiling is right underneath the metal roof. I have yet to figure out how tall the rafters are. Probably will have to cut into the ceiling to find out...

 

[begreen]

Yes, that If this is a metal roof you may want to get a flashing made specifically for that application. ICC Excel makes one. This picture is before the storm collar is in place. They were able to tuck the upper edge under the ridge cap in this installation.