Ridiculously tall flue??

Moorboy3 · Jan 7, 2014

I'd like to post this question as a newbie.

Attached is an architect's drawing of our redesigned house. Just bought it and having quite a lot of work done including installing a wood stove (prob Jotul F3 CB), and increasing the pitch of the roof. The stove will be against the outside wall making the flue incredibly tall as it comes out of the roof. It is roughly 10' to the peak from the roof exit, making the whole thing about 12' high - by my understanding of the regs. It looks kind of ridiculous. I'm worried that Homeland Security might think we have some kind of WMD project underway

My question involves whether the long exposed section of flue will work efficiently. I understand it is better to keep the flue running up inside the house which is what it does from the stove on the ground floor up to the attic. Someone suggested that the tall column of cold air sitting in the flue would make it not draw properly. It was also suggested that we could get bad drafts down the flue (presumably this makes it a non-starter).

One option would be to dog-leg it inwards at the attic then straight out a little higher up the roof but our roof is 45 degrees and I think the flue can only turn 30 degrees. Could be done but more expensive plus difficult to clean?
Another option would be moving the stove to an inside wall so that the flue comes out right near the peak. This makes things in our attic room very complicated so I'm trying to avoid it.

If we keep the current 12' design we will presumably need two levels of stays. Will I need access to the top of the flue for cleaning because this could end up getting complicated and expensive to do.

I've been staring at this for a while. Any new insights would be most welcome.

Ben

DAKSY · Jan 7, 2014

You need to be 144" (12') out of the roof on a 12/12 pitch. There is another option to what you've already listed, tho.
You can frame in a chase to enclose most of the Class A. It'll look a lot better than the SS Scud Missile you'll have there...
A framed chase should have more support for a ladder to access the cap for maintenance as well...

Dakotas Dad · Jan 7, 2014

I would see what could be done with moving the stove to the center of the house.. That is the best placement anyways. Sit it so a chase can be built out from a wall or corner to conceal/house the chimney.

Ashful · Jan 7, 2014

I would move to the peak for two reasons:

1. Access for cleaning, maintenance, repair. That thing is going to be a nightmare to access, even with a framed chase.
2. Cosmetics. It looks silly. A chase won't make it worse, but it will still look like a stupid afterthought.

Hardrockmaple · Jan 7, 2014

My masonry chimney is 42 ft. from top to bottom up thru the house which is a Double A frame with 21/12 pitch. The sweep basically has to build a work platform at the roof and chimney to do any work up there. A real pain in.....

If it were me I'd try to figure out a way to fun that up thru the house, if at all possible.

Jags · Jan 7, 2014

This is a bit off topic but... do your homework on the FC3B. They are a mighty little stove...but little. ~3 hour burn times. Not sure of the use you have intended for the stove, but this will not be a house heater. I just don't want you to be disappointed with its performance.

jzinckgra · Jan 7, 2014

We have a corner install on a 12/12 pitch roof and have 13' of exterior pipe. Doesn't look great, but you get used to it. The cleaning guys won't be happy to clean it, but I've been doing it myself lately from the bottom up.

Cynnergy · Jan 7, 2014

I agree that you should try to put it inside the house if possible, however, we had a similar issue at our cabin and have about 6' double wall and 2' chimney inside, and another 8' chimney outside (8/12 roof). It doesn't look fantastic, but it's not terrible either. If you do decide to go this way, you might want to make sure your stove is easy to clean from the bottom-up - some are easier than others to remove the baffle, etc. Don't forget that you will need to add braces if it's not inside a chase, so that's more visual clutter.

I don't think you'll have a problem with draft once the stove is going - all told you are looking at a 30' flue system, which is quite tall for modern stoves. As long as your chimney is above the peak of the roof, I believe you shouldn't have a problem with flue reversal. Check out this article for an explanation of the stack effect: http://woodheat.org/how-chimneys-work.html.

You might have to be careful if you have other flues (don't see any on the drawing ) and a really tight house - sometimes they can compete for air and one appliance can pull air down the other flue.

Excuse the mess - we were in the middle of redoing the roof and outside of the cabin is still a work in progress.

jzinckgra · Jan 7, 2014

Here's a pic of our stack on a 12 pitch roof. I don't think it's terribly ugly. Certainly functional. Before anyone asks, yes, a rain guard and bracing were added to the stack after pic was taken.

Ashful · Jan 7, 2014

Very cool house! Awful stove pipe... but very cool house. Must be fantastic sitting inside by the stove, and looking out at that view.

jzinckgra · Jan 7, 2014

Joful said:
Very cool house! Awful stove pipe... but very cool house. Must be fantastic sitting inside by the stove, and looking out at that view.

C'mon, it's not that bad. lol. Thought about a chase, but that would then have to be braced and ther'd be more surface area for the wind to attack.

mark cline · Jan 7, 2014

jzinckgra said:
Here's a pic of our stack on a 12 pitch roof. I don't think it's terribly ugly. Certainly functional. Before anyone asks, yes, a rain guard and bracing were added to the stack after pic was taken.

We were faced with the same dilemma . The chalet in the above picture is almost identical to my loghome minus the dormer on the right. We put on a large dormer on the left to enclose the chimney pipe and that will allow me build a stone chimney inside up to the roof line with class A pipe exiting the roof. The dormer and roof are on and stone chimney will be built this spring and summer. Then we'll move the Mansfield in when we move ourselves in.

Ashful · Jan 7, 2014

jzinckgra said:
C'mon, it's not that bad. lol.

You have an advantage with that steeply pitched roof, in that you can hardly see the stove pipe peeking out behind it.

Cynnergy · Jan 7, 2014

jzinckgra said:
C'mon, it's not that bad. lol.

I think it's ok. But then I'm biased...

Moorboy3 · Jan 7, 2014

Jags said:
This is a bit off topic but... do your homework on the FC3B. They are a mighty little stove...but little. ~3 hour burn times. Not sure of the use you have intended for the stove, but this will not be a house heater. I just don't want you to be disappointed with its performance.

The stove won't be the primary source of heat for the house. It's just to make our main kitchen-dining room space more warm and friendly - It's about 10'x30'. Do you think it would be ok for that? I don't want some furnace that blasts everyone out of the back door! Anything you'd recommend, perhaps for a longer burn time?

Ben

Moorboy3 · Jan 7, 2014

jzinckgra said:
C'mon, it's not that bad. lol. Thought about a chase, but that would then have to be braced and ther'd be more surface area for the wind to attack.

Did you need to use two levels of stays/bracing for this flue? I don't think it looks bad at all. We were thinking of painting ours black. Do you know if that is possible, or does it need to be stainless for some reason?

Jags · Jan 7, 2014

Moorboy3 said:
It's just to make our main kitchen-dining room space more warm and friendly - It's about 10'x30'.

If you are just looking for some short term heat in the 10 x 30 - that might be a good choice. It really is a nice little stove but pretty notorious for short burn times.

Cynnergy · Jan 7, 2014

Do you have some floor plans you could share? If the house is relatively open plan, you could definitely go bigger and not be blasted out of the room. Heck, our cabin is about 900 sq ft in a mild climate and we have a 2 cubic foot stove in order to get overnight burns. If it gets too hot, we just let the stove die out, or at night, close the door to our bedroom.

jzinckgra · Jan 7, 2014

Moorboy3 said:
Did you need to use two levels of stays/bracing for this flue? I don't think it looks bad at all. We were thinking of painting ours black. Do you know if that is possible, or does it need to be stainless for some reason?

Only one brace was used about half way up. Not sure about painting. May not hold up to the elements.

Ashful · Jan 7, 2014

Moorboy3 said:
The stove won't be the primary source of heat for the house. It's just to make our main kitchen-dining room space more warm and friendly - It's about 10'x30'. Do you think it would be ok for that? I don't want some furnace that blasts everyone out of the back door! Anything you'd recommend, perhaps for a longer burn time?

You will have trouble finding another functional stove more attractive than the FC3B, that actually works well, but depending on your stylistic taste... the Woodstock Fireview? It's a smaller catalytic stove, and all reports are it's very controllable in pretty small spaces.

If you're like a lot of us, you start out thinking it will be for just occasional ambiance, and then you get hooked. Next thing you know, you have 18 cords of wood stacked in the back yard, and realize you haven't seen the oil man yet this year.

tsquini · Jan 7, 2014

Moorboy3 said:
I'd like to post this question as a newbie.

Attached is an architect's drawing of our redesigned house. Just bought it and having quite a lot of work done including installing a wood stove (prob Jotul F3 CB), and increasing the pitch of the roof. The stove will be against the outside wall making the flue incredibly tall as it comes out of the roof. It is roughly 10' to the peak from the roof exit, making the whole thing about 12' high - by my understanding of the regs. It looks kind of ridiculous. I'm worried that Homeland Security might think we have some kind of WMD project underway

View attachment 123171
My question involves whether the long exposed section of flue will work efficiently. I understand it is better to keep the flue running up inside the house which is what it does from the stove on the ground floor up to the attic. Someone suggested that the tall column of cold air sitting in the flue would make it not draw properly. It was also suggested that we could get bad drafts down the flue (presumably this makes it a non-starter).

One option would be to dog-leg it inwards at the attic then straight out a little higher up the roof but our roof is 45 degrees and I think the flue can only turn 30 degrees. Could be done but more expensive plus difficult to clean?
Another option would be moving the stove to an inside wall so that the flue comes out right near the peak. This makes things in our attic room very complicated so I'm trying to avoid it.

If we keep the current 12' design we will presumably need two levels of stays. Will I need access to the top of the flue for cleaning because this could end up getting complicated and expensive to do.

I've been staring at this for a while. Any new insights would be most welcome.

Ben

It sound like no matter what you do, if you go with a wood stove it will be complicated. If you went with a pellet stove you don't need the chimney. You could vent though a wall.

For a wood stove you could vent the pipe through a wall and go up. That way you can brush it from a clean out on the bottom. You would see more pipe but the long-term maintenance would be easier.

begreen · Jan 7, 2014

I can't see building in a defect in a new house intentionally. The stove and chimney will perform better located centrally in the house.

Ridiculously tall flue??

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