Damaged internal lining on 8" double-walled pipe

[WhatDayJob]

I was prepping my stove and chimney for the upcoming season, and I have a pretty nasty internal issue.
It's an 8" pipe going into a T-piece that has a cleanout at the bottom and a horizontal run to the stove.

View 1 shows where the pipe's internal lining is starting to come away. I noticed this last season and my sweep said it wasn't a concern, but it's looking pretty significant to me, and it's a weakness near the hottest part of the system, which I don't love.
There's also that random bolt sticking through the pipe that's been there since we bought the house. Don't love that either.

Do we simply need to replace the first length of pipe, or could I find a high-temp fastener, to either pin the loose pieces back against the wall or draw them back against the wall of the pipe from the outside. Third alternative could be to put a metal band of the right diameter in there to force the metal back into place, but I'm hesitant to introduce aftermarket materials into my piping. Seems like a bad idea.

View 2.jpg just shows a temporary brace I put in to see if I could reform the metal back to where it should be. I have no intention of leaving it there.

 

[begreen]

That section of pipe should be replaced with the same company's matching chimney pipe. Screws should not penetrate the inner liner, which is what appears to have happened here.

 

[bholler]

I was prepping my stove and chimney for the upcoming season, and I have a pretty nasty internal issue.
It's an 8" pipe going into a T-piece that has a cleanout at the bottom and a horizontal run to the stove.

View 1 shows where the pipe's internal lining is starting to come away. I noticed this last season and my sweep said it wasn't a concern, but it's looking pretty significant to me, and it's a weakness near the hottest part of the system, which I don't love.
There's also that random bolt sticking through the pipe that's been there since we bought the house. Don't love that either.

Do we simply need to replace the first length of pipe, or could I find a high-temp fastener, to either pin the loose pieces back against the wall or draw them back against the wall of the pipe from the outside. Third alternative could be to put a metal band of the right diameter in there to force the metal back into place, but I'm hesitant to introduce aftermarket materials into my piping. Seems like a bad idea.

View 2.jpg just shows a temporary brace I put in to see if I could reform the metal back to where it should be. I have no intention of leaving it there.

View attachment 299693 View attachment 299694

Yeah no question that section needs replaced. I would check every section closely for damage. Also if one is heavier than the rest that means water has gotten to the insulation and it should be replaced as well

 

[WhatDayJob]

Yeah no question that section needs replaced. I would check every section closely for damage. Also if one is heavier than the rest that means water has gotten to the insulation and it should be replaced as well

Thanks for the response. We live in a pretty remote area, so getting someone out to service the system often takes quite a bit of time and money. Assuming it's just a matter of an in-line swap out of pipe lengths, is this something that I could do myself, or is there a nuance/inspection requirement that requires a professional?

 

[begreen]

The replacement can be DIY if the chimney can be lifted up about 4" and held in place temporarily. But, that does not get the other sections inspected for issues. Seems like there is a chance they drove a screw or more in at other locations too. Maybe at the support brackets?

 

[Riverbanks]

Can you provide a outside picture of the chimney?

 

[WhatDayJob]

The replacement can be DIY if the chimney can be lifted up about 4" and held in place temporarily. But, that does not get the other sections inspected for issues. Seems like there is a chance they drove a screw or more in at other locations too. Maybe at the support brackets?

The one other screw that's just above that T-piece doesn't seem to be attached to anything else. I haven't removed it because I don't want to open a path to the outside of the pipe if I don't have to. I ran a camera down the length of the pipe today and didn't notice any other penetrations.

If the pipe hangers and screws are the only connection points, I could disassemble it piece by piece for inspection and weighing. The bottom of the T-piece is braced on two metal brackets, so I could start at the top and work my way down.

 

[WhatDayJob]

Can you provide a outside picture of the chimney?

Thanks. I was having issues last year (clogged critter guard), so I created a whole album of images. they're all of the inside, but they'll give you a sense of the pipe run.

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Basically a one-story house with an unsealed attic. The stove outlet is horizontal through the thimble, then into the T-piece, which has the cleanout cap on the bottom.
The pipe run vertically through the attic and then out the roof.

 

[bholler]

Thanks. I was having issues last year (clogged critter guard), so I created a whole album of images. they're all of the inside, but they'll give you a sense of the pipe run.

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Basically a one-story house with an unsealed attic. The stove outlet is horizontal through the thimble, then into the T-piece, which has the cleanout cap on the bottom.
The pipe run vertically through the attic and then out the roof.

Well I can tell you that all the spray foam needs to be removed. That absolutely cannot be within 2" of the pipe

 

[WhatDayJob]

Well I can tell you that all the spray foam needs to be removed. That absolutely cannot be within 2" of the pipe

Right!? I'm not even a professional, but I at least read the manual. As soon as I climbed into the attic I realized that wasn't up to snuff.
You can see my comment on the picture that it needed to be cleared out. It gave me a hinky feeling about the entire setup and whether whoever did the install bothered to look at any codes or manufacturer's guidelines.

 

[bholler]

Right!? I'm not even a professional, but I at least read the manual. As soon as I climbed into the attic I realized that wasn't up to snuff.
You can see my comment on the picture that it needed to be cleared out. It gave me a hinky feeling about the entire setup and whether whoever did the install bothered to look at any codes or manufacturer's guidelines.

I didn't see the comment but glad you knew that. Lots of people think because it's fire foam it is fireproof. But it absolutely isn't

 

[begreen]

Wow. It also looks like there is creosote dripping down the chimney pipe. The storm collar may be improperly sealed. I think the idea of removing it all for inspection and weighing is a good one. A proper firestop with attic insulation shield should be in place of the foam.

 

[WhatDayJob]

Wow. It also looks like there is creosote dripping down the chimney pipe. The storm collar may be improperly sealed. I think the idea of removing it all for inspection is a good idea. A proper firestop with attic insulation shield should be in place of the foam.

Thanks for reviewing everything. The inside of the pipe is surprisingly squeaky clean. I had it professionally swept last year, and did it again today myself, which is when I started looking closer at the torn metal. The storm collar is about as basic as it gets. I bought a replacement but haven't installed it yet.

So, if I have to tear the whole thing out...
Right now it's an 8" pipe. My stove could also use a 6" pipe (the 6" flue collar is about 200$ US), and it seems like most modern stoves use the 6" chimney as well.

Thinking ahead to my next stove, since this one's in rough shape and as old as I am, would it make sense to replace the entire run of chimney pipe with 6" double-walled pipe, knowing that I'm going to be upgrading to a new EPA stove or insert in the next few years? I'd hate to drop a grand on new 8" pipe just to tear it out soon after.

 

[Riverbanks]

That is a great idea, new 6" class a, how old is the system that is there?

 

[begreen]

Replacing it with new pipe will provide more peace of mind and it would be better matched to most modern stoves. However, finding the right replacement stove with a rear exit may be a challenge due to varying heights of the flue outlet between stoves.

The MetalFab TG chimney is still sold. It's about $170 for a 36" length of 6". Not sure about 8". The storm collar is cheap, about $30. This is not the flashing, just the collar that diverts the rain away from the pipe. Call here for pricing.
(broken link removed)
Still, when one adds up the pipe section, storm collar, and attic shield it does add up.

 

[WhatDayJob]

Replacing it with new pipe will provide more peace of mind and it would be better matched to most modern stoves. However, finding the right replacement stove with a rear exit may be a challenge due to varying heights of the flue outlet between stoves.

The MetalFab TG chimney is still sold. It's about $170 for a 36" length of 6". Not sure about 8". The storm collar is cheap, about $30. This is not the flashing, just the collar that diverts the rain away from the pipe. Call here for pricing.
(broken link removed)
Still, when one adds up the pipe section, storm collar, and attic shield it does add up.

Yeah, that's why I'm tempted to go for the future-proofed option. Would you recommend Servicesales.com for a pipe purchase? The big box stores have little to choose from, and I don't know the reputations of anyone else.

Regarding the rear exit - If I were installing this stove in a new build, I would have skipped the horizontal run and gone vertical from the outset. I'm not sure why they went with the option that takes up more space in the living room and the room behind the wall. If/when I get a new stove/insert, I plan on ripping out all the outdated rock and putting in something that makes sense. Including a vertical pipe.

 

[WhatDayJob]

Replacing it with new pipe will provide more peace of mind and it would be better matched to most modern stoves. However, finding the right replacement stove with a rear exit may be a challenge due to varying heights of the flue outlet between stoves.

The MetalFab TG chimney is still sold. It's about $170 for a 36" length of 6". Not sure about 8". The storm collar is cheap, about $30. This is not the flashing, just the collar that diverts the rain away from the pipe. Call here for pricing.
(broken link removed)
Still, when one adds up the pipe section, storm collar, and attic shield it does add up.

I'm looking at the MetalFab documentation now. It says the pipe is rated for 1000° continuous, 2100° intermittent. How do the manufacturers define "intermittent" vs. "continuous"?

 

[bholler]

I'm looking at the MetalFab documentation now. It says the pipe is rated for 1000° continuous, 2100° intermittent. How do the manufacturers define "intermittent" vs. "continuous"?

That is appropriate for use with a woodstove

 

[WhatDayJob]

That is appropriate for use with a woodstove

Yeah, I figure they wouldn't sell the pipe if it wasn't. Really just asking out of curiosity. Have you had good purchasing experiences with servicesales.com?

 

[bholler]

Yeah, I figure they wouldn't sell the pipe if it wasn't. Really just asking out of curiosity. Have you had good purchasing experiences with servicesales.com?

I really only buy from professional suppliers. And there is high temp pipe used for woodstoves and low temp for fireplaces