# calculating wood stove pipe & chimney pipe lengths



## fireinmybelly (Jul 15, 2011)

hello everyone,
  what are lengths of pipe needed for 6" Diameter Decorator Ceiling installation of single stove pipe & double chimney pipe ?
it seems the location where the chimney will emerge from the roof is just on the other side of the apex.
here are the dimensions:
1.per englander 17â€VL instrux "We require a minimum chimney height of 15.0 ft."     englanderstoves.com/manuals/17-VL.pdf 
2. pipe size=      6 inch
3.Single wall stove pipe
4.englander stove height (bottom of stove to spot where pipe connects to stove)=  31.75"
5.room height=   90"
6.Height from stove top to ceiling =   ~58.25"
7.(how to accurately measure attic height from ceiling to roof-- i reached thru the insulation to the floor of the attic & stretched to the top of the attic where the chimney would go thru & it seems like it's   ~59"
8..Ceiling pitch-slope =    flat
9.Roof pitch  =  5/12
10.ceiling to floor beneath where hearth will be locatedr=                  92â€

thanks


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## mhrischuk (Jul 15, 2011)

fireinmybelly said:
			
		

> hello everyone,
> what are lengths of pipe needed for 6" Diameter Decorator Ceiling installation of single stove pipe & double chimney pipe ?
> it seems the location where the chimney will emerge from the roof is just on the other side of the apex.
> here are the dimensions:
> ...



I use a plumb bob to measure between surfaces.

I believe you can get a piece of telescoping single wall that fits that range. 


For the class A chimney (not necessarily your question)

Stove pipe inside counts as part of the chimney length.

Your main driver is the 15 feet minimum.
Your modifier is the 3 foot minimum above the roof and 2 foot higher than 10 foot horizontal. If at 50" high vertically off of the roof you hit the roof 10 feet away, you need to add 2 feet.

You know you have 58" from stove top to ceiling.
From the ceiling you start your Class A chimney pipe.

For 15 feet you simply subtract the 58" of inside stove pipe from the 15 feet total to determine the minimum Class A you need to end up with the total chimney height.

15' = 180"- 58" = 122"
122"/12"=10'

Answer.. 10 feet of Class A.

You just met the main driver.

Lets look at the roof clearance rule now....


A 5/12 pitch is around 30 deg pitch. It means the roof rises 5" for every foot horizontal. The rule is 3 feet minimum above the roof and 2 feet higher than 10 horizontal.

Question: Will the calculated 10 feet from your ceiling support box meet this requirement?

What's missing in your provided data is what type of roof. Standard gable end roof? Only one roof?

If so then, a 5/12 pitch would give you 50 inches of height to get the 10 foot horizontal.
Remember a 5/12 pitch, for every 5" you go straight up the roof is 1 foot farther away so 5" x 10 = 50" high. 
Then add 2 feet
50" + 24" = 74"

Now you know 74" is how much you need protruding through the roofline to meet the horizontal rule, if at 50" the roof is there 10 feet away on a horizontal plane.
This easily meets the 3 foot minimum above the roof.

You have 59" under the roof.

59 + 50 = 109"    you already are 122" so you are good with 10 feet of class A.

In the end, since you mentioned you are close to the apex, or peak, the 2 feet over 10 horizontal is pretty much negated and you end up looking at the 3 foot minimum and the 15 foot overall.

Let the experts check my math before you move ahead.

Mike


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## begreen (Jul 15, 2011)

When measuring, remember the 10-3-2 rule: Chimneys shall extend at least three feet above the highest point where it passes through the roof of a building, and at least two feet higher than any portion of a building within ten feet. 

Also note that in general it helps to exceed the minimum height even by a foot or two for better draft during the shoulder seasons. If the pipe is 5 ft or more, it must be braced at every 5 ft above the roof.


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## fireinmybelly (Sep 7, 2011)

Thanks for your replies.  After the last 2 months of research and planning, I finally finished installing the chimney today.  I have total of 10 feet of class A chimney.  Before starting the project it looked like I'd have about 5 1/2 feet of chimney extend the roof line, and ordered a universal roof guy kit from Selkirk just in case.  Since the install today, I actually have 54" of chimney measured from the upper slope, 60" with rain cap.   Do I need to install the roof support? I don't want to install the roof support if I don't need to.
Thanks


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## begreen (Sep 7, 2011)

Technically no, you are ok without the support. But if you are in the snowier or windier parts of WA it wouldn't hurt and might give better peace of mind when the weather is really snotty.


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## mhrischuk (Sep 7, 2011)

I would consider where you live and the weather as a factor. Even though you are a few inches under the rule for supports, you are on the cusp. Better secure than wondering all the time. Consider wind forces. The chimney might make creaky noises and/or the seal at the storm collar could separate from movement. Can you get us a picture? I would like to see where the seams are.


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## fireinmybelly (Sep 8, 2011)

Western WA can get windy in winter.  It can't hurt to install it for piece of mind like Be Green mentioned. Here are 2 pics of the chimney.


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## begreen (Sep 8, 2011)

We are exposed to direct shots from the north clear to Alaska at our house. So I keep in mind the 100mph gusts that took down Hood Canal Bridge. But you look to be in better shape. Still, there is no harm in putting up the brace. Later on, if you find you want to install another couple feet after burning this season, you'll be all set.


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## mhrischuk (Sep 8, 2011)

fireinmybelly said:
			
		

> Western WA can get windy in winter.  It can't hurt to install it for piece of mind like Be Green mentioned. Here are 2 pics of the chimney.



Nice work. I wood install the support kit on that. Maybe not so much for the structural support but more for preventing movement that could break the seal of your caulking over time. You might even get noises as the chimney rocks ever so slightly. Those flashings aren't all that tight on the chimney and are flexible in themselves.


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