# Silicon Boot for Woodstove Chimney Flashing?



## simi-steading (Sep 27, 2012)

I am putting a wood stove in my pole barn,and of course, flashing for metal roofs is a real issue... and not a cheap one at that.. 

I've found these silicone boots that claim to be around 500F+ ... so I am wondering, is that really hot enough protection?

The boot will be about 10 feet above the stove. It will be an 8" pipe.

I don't plan to use a double or triple wall pipe through he roof, just a single wall, with the boot as my flashing.

I just can't see that the pipe would be 500F... Do you think I'd be fine with this? Or do you think I really need a double wall pipe for the part through the roof because of the boot? I really hate to use a double wall pipe because it will create another place I will need to worry about water.... I'ts not easy to seal a double wall to a single wall, unless you order special couplers. (mo' money)


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## Nimrod (Jun 8, 2010)

The thermometer on my single wall about a foot above the stove can hit 700 degrees if I let the fire really roar. Seems like it could exceed 500 where it goes through the roof.

I think it would certainly exceed 500 if you had a chimney fire. Not sure what it would do then, melt and catch fire? 

You should splurge on the double wall through the roof. If it needs sealing use a high temp silicon caulk.

http://www.acehardware.com/product/...43&cp=2568443.2568453.2627947.2627970.2627967


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## Fishindude (May 19, 2015)

That is a high temp decktite boot.
If that is triple wall penetrating your roof (which it should be) it will work just fine.
Make sure you install it in a manner where water can't puddle on the uphill side of it. The run-off water needs to be able to flow around this thing.

I've been up on my roof when wood stove is burning. You can put your bare hand on the triple wall flue and it's just warm, not overly hot. Pretty amazing insulation actually.


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## Harry Chickpea (Dec 19, 2008)

"I don't plan to use a double or triple wall pipe through he roof, just a single wall, with the boot as my flashing."

Bad move. Aside from not being code, by not using some sort of insulation, the pipe will be COOLER that normal. That means poor drafting performance and more importantly major creosote condensation on the interior of the pipe. Your silicon boot will be just fine ... UNTIL ... you have a chimney fire and all h*ll breaks loose.

Simply put, even promising myself I would do weekly cleanouts of the pipe, there is no way I would even consider such a setup.


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## Darren (May 10, 2002)

Got insurance? If you have fire insurance, there's a real possibility the wood stove will trigger an inspection. Then you are on the wrong end of the "Pay me now, or pay me much more later." 

If your carrier extends coverage, and they are not aware of the wood heater, and you have a fire because of it, you may have wasted your money on the premiums.


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## simi-steading (Sep 27, 2012)

No insurance.. I take the risk on my dime.. You know my insurance would be ungodly Darren.. No hydrant, and no place without a drive to pump...

There is nothing near the pipe through the roof to worry about... It would just be metal roof... 

Yeah, I was wondering about the exhaust gasses getting too cool and causing more build up with a 12 foot or so pipe... I was actually wondering more about that, than if the pipe would be too hot 9-10 feet up

Guess I'll break down and do at least a 2 foot piece or two of double wall...


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## Darren (May 10, 2002)

You should be close enough to the station for insurance purposes. With the stream, you might be about to bluff them. By now you've probably seen enough to figure your own risk. You know about old places.


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## Bearfootfarm (Jul 13, 2006)

It would be foolish to risk the entire house to save just a few dollars on a proper chimney


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## simi-steading (Sep 27, 2012)

It's not a house.. it's a pole barn.. Big open building with pretty much no insulation.. Metal roof.. Perlins 2 feet apart.. If I take a chimney through the roof that's in a 9" hole.. what's that leave between perlins? 7.5" away from the closest 2x4 , 9 feet or so above the stove..


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## Harry Chickpea (Dec 19, 2008)

Open pole barn is a _lot_ different than a house. This is a way that can work:










(source page: http://www.garagejournal.com/forum/showthread.php?p=1243971 )

Note the straps bracing and holding things up, the metal thimble and one section of SS insulated pipe. I would just use part of a sheet of 18 ga galvanized to make a square under the metal roofing with more strength, and attach that to the purlins on either side. I would also have a draft damper in the pipe as high up as I could reach comfortably AND I'd plan on replacing the pipe at the first sign of weakness.


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## simi-steading (Sep 27, 2012)

Nice picture Harry.. THANKS!... Great idea on how to brace the pipe. I was trying to figure out how I was going to do that...... and now I know 

I have realized I will need to use double wall. Not because of the risk of burning a metal roof, but rather to keep the exhaust hot enough to keep a good flow, and so I don't get so much creosote.


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## Fishindude (May 19, 2015)

Those single wall flues get very hot and would likely melt that boot as well as endanger any wood framing or deck within 2' of the flue. Harry's picture shows how to do it correctly, and it's stainless "triple wall" flue, not double wall. You can use single wall all the way up to the transition.


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## simi-steading (Sep 27, 2012)

OUCH did that just hurt... Got everything ordered, including 60" of double wall for through the roof... I just couldn't justify the cost or very little added protection for triple wall over the Duratech double wall.. Ended up only costing me about $650 or so.... :Bawling:

I mean, come on... over $100 for a rain cap/spark arrestor?????


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## Harry Chickpea (Dec 19, 2008)

Yeah, I tell people that in a home situation to expect to pay as much or more for the chimney/flue as the stove. Lots of legal requirements and liability for the manufacturers and almost zero "used" market sales to keep prices down.


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## kasilofhome (Feb 10, 2005)

Harry Chickpea said:


> Yeah, I tell people that in a home situation to expect to pay as much or more for the chimney/flue as the stove. Lots of legal requirements and liability for the manufacturers and almost zero "used" market sales to keep prices down.


Very true... I spent over 1500 on my stack 5000 on the stove. Fire scares me.. it gets clean the first Saturday of the month.


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## GREENCOUNTYPETE (Jul 25, 2006)

there is nothing cheap about a good chimney it can easily cost more than the stove but a good metal chimney does last a very long time , my grandparents have a double wall that was installed in the early 80s and used very heavily since and it is still fine 

mine is now 7 years old the stack was 2200 installation was 500 (professional installation made my insurance company happy no rate increase) and the stove was a used floor model for 999 but it saved enough that it was nearly break even the first year , because fuel oil had jumped to over 4 dollars a gallon that year we were saving money the second year.


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## Bearfootfarm (Jul 13, 2006)

> I mean, come on... over $100 for a rain cap/spark arrestor?????


Prorated over it's life span will work out to pennies per month


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## Snowfan (Nov 6, 2011)

Just out of curiosity, how far is the stove from an exterior wall.


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## simi-steading (Sep 27, 2012)

The back of the stove sits about 2 feet from the outside wall.

It's an old Bat Cave stove. It's a double wall kind of stove, that has a squirrel cage fan on the back, that blows in between the walls and out the front.

Yeah, Good chimney isn't cheap, but man, for a free stove that was given to me, I would have like to be into this for a lot less...


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## GREENCOUNTYPETE (Jul 25, 2006)

simi-steading said:


> The back of the stove sits about 2 feet from the outside wall.
> 
> It's an old Bat Cave stove. It's a double wall kind of stove, that has a squirrel cage fan on the back, that blows in between the walls and out the front.
> 
> Yeah, Good chimney isn't cheap, but man, for a free stove that was given to me, I would have like to be into this for a lot less...


but a fire would cost a lot more 

look at it this way I think it is still cheaper than a free dog


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## simi-steading (Sep 27, 2012)

I just keep trying to look at it as the price of staying warm..... I just hope it warms up enough in there to justify all the parts, work and wood..


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## Harry Chickpea (Dec 19, 2008)

You might want a cheap ceiling fan as well. With a thin roof, it would seem smart to mix that hot rising air into the room before it gets cooled by the tin.


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## simi-steading (Sep 27, 2012)

I have double bubble vapor barrier through the whole building so that should help a little.. but I was thinking about a fan or two to try and keep some of the warm air a little lower...


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