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leaky wood stove chimney

benak's picture

My one year old Simpson-Duravent chimney system leaks, and I'm wondering if anyone else has experienced a similar kind of leak, and what their fix was.  Over the summer water has followed my 16' chimney, through the mounting box, down the stove pipe and onto my stove.  I assumed some detail of my flashing was at fault.  So I crawled in my attic on a rainy day and saw that the flashing appears watertight, but that water was dripping out of the seam between the top two 4' lengths of chimney.  This seam is about 8" below the flashing.  I do have a chimney cap that matches the chimney.  I'm guessing that the top of the chimney isn't watertight, and water is running through the chinmey insulation.  I'll contact the manufacturer tommorow.


Thanks for any ideas you may have,


Ben 


 


 

(post #113410, reply #1 of 8)

My first thought was that it was leaking in the outside of the pipe at the trim collar, but if you are certain no water is running in on the pipe exterior for that first 8", it is not that, tho that is the most common.

Duravent may have changed their pattern for joints since i was handling them. Do you know if the joint twists together with about a 4-6" clockwise rotation? or does it more or less just smnap together? It is important to have it tight and lined up correctly, because the air flow channels ( this is not a solid pack insulated pipe, but a triple wall cooled by air exchanges) could divert some water via their partition supports inside.

Nevertheless, the water should not be getting into the pipe in the first place. That means that the wind is a howling, or the rain cap is not installed right, or it is the wrong cap for the pipe.

every piece should havve a part number stamped into it someplace, so you can have them check that you were sold the right parts.
And every joint should be secured with a minimum of three sheet metal screws once it is all put together right.

 

 


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(post #113410, reply #6 of 8)

Thanks for the ideas.  This pipe is double walled, with insulation.  The connections screw together as you described.  And it's not upside down.  If I'm not mistaken, this system does not require sheet metal screws.  With the chimney support bracket is installed, I don't think there is much wiggle room for the sections to come untwisted anyway.  I was recently on the roof where I reattatched the top section and the chimney cap firmly.  And yes, the leak is from the horizontal joint, not the vertical seam.  I will check out the cap to ensure it's the right one.  It does screw positively into place, like the chimney sections do.  Oh and yes, the wind regularly howls over my roof. 


Ben

(post #113410, reply #7 of 8)

Hmmm, I'm out of ideas.

But most codes require that joints be secured with the SM screws after twisting them together

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #113410, reply #8 of 8)

Thanks.  I'll look into that.  When I did the installation, I just followed the manufacturers instructions. 


Ben


 

(post #113410, reply #2 of 8)

Just to be sure we're talking same thing - The seams run vertically the length of each pipe section, while the name of where the two pieces join is called a joint, which you referred to as a seam. The water appears to come from the horizontal joint, right? Not the vertical seam?

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #113410, reply #3 of 8)

I don't have an answer to your question, but I do have a Simpson DuraVent stack and it's for a propane stove. The woodstove has a Metalbestos Ultra HT stack. They are very different materials. Like Piffin says, the DuraVent is a concentric vent with no insulation... mine has combustion air intake on the outside and exhaust on the inside.


My DuraVent rain cap is a type that I would not expect to leak... it does not leave any of the top of the pipe exposed, but rather sits down flush with the top of the last section of pipe.


Now, sort of along the lines of what you are experiencing, my woodstove chimney is leaking around the storm collar, which is a b!tch because it's really dangerous to get up there to fix it, which I'll have to do.


I guess it's worth asking if you're sure that your chimney is not reverse assembled. I once saw a 6" B-vent from a boiler that had been installed upside down.

(post #113410, reply #4 of 8)

"it does not leave any of the top of the pipe exposed,"

That's right. The end should not be exposed to the rain or wind. I'm mostly suspecting he has been sold the wrong cap.

you also reminded me how many times I have seen pipe installed upside down, but that usualluy resuilts in creosote running out, rather than water leaks

 

 


Welcome to the
Taunton University of
Knowledge FHB Campus at Breaktime.
 where ...
Excellence is its own reward!

 

 

Oh Well,

We did the best we could...

(post #113410, reply #5 of 8)

I don't think the type I'm describing could be used with solid fuels. Actually, I'm surprised to read that Duravent is also a woodstove chimney. I have Duravent, Metalbestos, and Protech flues for three different appliances here, and they are very different materials.