Chimney height?

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Macman125

libertarian/anarcho-capitalist firewood hack
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garage.png

I know it is crude, but I am not there to take pics. How high should I go with the flue? Higher than the peak of the main roof? If so that is a lot of pipe to support. it is a locke warm morning pictured in the top pic below, very similar to the one below it.wood stove.jpg wood stove 2.jpg
It is at a buddy's garage, we have had it setup for a few years now. It is a block wall garage. We had it plumbed with 8 inch single wall through the wall and up just like top pic. Well finally the wind and weather have gotten the better of it. It has always had a draft problem (smoking up the whole garage till warm) and now that I need to rebuild it, I was wondering how high I should go with it? I am certainly over having to deal with the smoke. Any help would be much appreciated.
 
there is plenty of flue height advice online, just search it out. generally, for fireplace flues you go couple feet above highest roof line peak. I am installing a wood stove, too... and plan to go above roof line. support will be required per your design. real issue is the wind. winds, depending on direction can hit the roof line and tumble, crashing into a too short flue top and cause backdrafts down thru the flue into the house's interior. not desirable. however, proximity to the roof's peak has to be factored in. a larger cap may be helpful, too.

btw - like that stove. :) its a sharp looking one. mine has an oval top too, wonder how u will flash to it and what type of flue pipe you will select?

hope you will continue this thread with posts & pix for the redo!! :) this may help u get going in the right direction:

http://inspectapedia.com/chimneys/Chimney_Height_Codes_Specifications.php
 
I have forgotten the specs but it was something like 3' above the nearest obstruction within X feet of the chimney. I don't recall the distance of the X anymore. From your drawing it looks like it meets or exceeds that requiremnt. With draft problems the answer is usually adding more height.

Googled it. Code: 3' above where it exists the roof and 2' above any obstruction withing 10'

Google "chimney height' will give you lots of information which pretty much boils down to "add height'.

Part of the problem might be that short horizontal run, would be better going straight up.

Harry K
 
General guideline is 2' above anything within 10'. In your situation that doesn't give you much chimney to get a good draft going.

We have 22' of class A double wall for the wood stove outside the house. It has 1 roof support tied into the fascia probably 12' up and its been solid as a rock. And we get some hellacious winds through here.
 
Here too, 80-100mph gusts. Last winter the 3ft piece I added on the shop blew right off. Apparently 5ft was too tall with no brace.
 
I have a pretty good idea of how I am going to support it. I am still going to use single wall as it goes through a block wall. It may sound a little redneck but I am going to make a support by welding a 1" cap inside of a rim, then get a 12' section of 1" pipe, screw it into the cap so it will stand upright, then every so often I will clamp it to the flue.
I figured I needed to add more height, I just don't know if I need to make it taller than the main peak. Code around here as well says 2' above anything within 10'. Is that for best performance or fire hazard?
 
I have a pretty good idea of how I am going to support it. I am still going to use single wall as it goes through a block wall. It may sound a little redneck but I am going to make a support by welding a 1" cap inside of a rim, then get a 12' section of 1" pipe, screw it into the cap so it will stand upright, then every so often I will clamp it to the flue.
I figured I needed to add more height, I just don't know if I need to make it taller than the main peak. Code around here as well says 2' above anything within 10'. Is that for best performance or fire hazard?
performance,, or youll get backdraft...
 
Well if that is the case I was already within spec. I know I need to add more to it I just don't know if I need to go higher than the main peak.
 
I have a pretty good idea of how I am going to support it. I am still going to use single wall as it goes through a block wall. It may sound a little redneck but I am going to make a support by welding a 1" cap inside of a rim, then get a 12' section of 1" pipe, screw it into the cap so it will stand upright, then every so often I will clamp it to the flue.
I figured I needed to add more height, I just don't know if I need to make it taller than the main peak. Code around here as well says 2' above anything within 10'. Is that for best performance or fire hazard?
Single wall for a chimney definitely sounds red neck to me. The problem with single wall above the roof line is not fire hazard. The problem is that without insulation the wall of that pipe will get downright cold so you will have a condensing surface on the inside of the pipe to promote huge creosote build ups. Even if you choose to ignore all codes, which it seems you have, you still want a practical solution and single wall just is not that.
 
Double wall is expensive and I am not shelling out the money for it plus it is even more weight that I would have to support. I am helping a friend out who has no money so I am going at it cheap as possible, redneck or not.
 
Not much worried about creosote either because it is a block building with a tin roof and there will always be someone there to tend to the fire.
 
Since your 12 feet from a peak and are using single wall. Why not just go A few feet past the roof edge and see how it drafts. If it's good leave it if it's not just add another section or two?


Sent from my iPhone using Tapatalk
 
Harry K already mentioned an important point about the horizontal run. Strictly from a performance and draft standpoint, the ultimate solution is to go straight up through the roof - 100% vertical and 0% horizontal run, but that requires something completely different than single wall pipe going through the ceiling, and you mention that's not an option. So, if you're going out through a sidewall, the idea then is to keep the horizontal run at an absolute minimum. If you can't do that due to stove location or what have you, then ditch the two 90 degree elbows and replace them with 45's......you would go from routing smoke through 180 total degrees to 90 total degrees and this will significantly help with draft. You're going through a block wall and yes, it wouldn't be as easy as making a horizontal hole through the wall, but sometimes the easiest way is not the best way......you mention your main worry is about the smoke and draft problem and these suggestions will help mitigate those issues.
 
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