Clay Flue Has Cracks - Run stainless insert instead of removing all of the clay?

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WoodStoveLife

New Member
Nov 21, 2023
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Hello helpful Woodstovers!
We just moved into this house November 2022 the house was built in 2010ish, there is a double sided fire place and two wood stoves. The wood stoves run from the roof all the way to a clean out in the basement. They are lined with a clay flue. The first inspection had the 3 flues clean and in good condition. After one winter of burning there are a few cracks in the clay. The inspector recommended we knock all of the clay out and run a new flue. We are still waiting on a quote. As far as I can tell the flue is a straight shot up and down. Is running a stainless insert through the clay a option? I saw a lot of forums saying it is but I am still a bit confused. We are reaching out to the original company to see if they will come out. They were booked so we had to go with this new company.
 

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And you fell out of your chair?
 
And you fell out of your chair?
It was $11,000 to remove the clay flues install new stainless piping. Attached are the two cracked pieces of clay flue they found.
The three clay flues are different sizes and I am trying to get that info from them because they stated both would not fit a 6" insert. We have two Jotul F500s
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I believe the smallest clay flue is 8 x 8 with a inner of 7 x 7 but the opposite side looks large enough to fit a insert. I see that 6 inch duraliner pre-insulated might fit but probably not, could I do a 5.5" pre-insulated?
 
Had a feeling it would be high. I received one close to $6k with no clay tile removal and no block plate. I am no expert but if you install an insulated liner, why do the clay tiles need to be removed? Maybe they are sticking out into the chimney and will prevent installing the flue? Again no expert and I saw a video on how it’s done posted on here but not sure you can rent the device or not. A messy affair and all the tile lands down in your hearth.

As for the size of the liner, if you can run a 5.5” pre-insulated but that usually means the inner liner is much smaller, like maybe 4.5”? That will not work for a stove that requires 6” which is common. I just finished installing my liner and it was a bear of a job for me. I bought a pre-insulated liner that was 35’ as I wanted plenty of length and not be short. That thing is heavy when you are about 30’ up on scaffold and in the end I could not get it up and over into the chimney. Instead I ended up going from the bottom up and it was a challenge as the liner is 7.5” and I have plenty of room inside of 13”x13” but still the liner would rub up against the mortared section of the clay tile. I did eventually succeed but it involve a hand winch on top of the chimney attached to a wood frame and it was able to get it 90% there and then I used my tractor for the last 4’ as I just could not pull it up manually and the winch was out of line. Saying all this is if you have 6”x6” areas in your chimney then that may be why they are proposing removing the tile for more space?
 
Removing the clay liner is the correct course of action. You can think of all the ways it could be done without removing it but if it’s an 8x8 none of them rank above clay liner breakout.
 
Thanks guys I appreciate the responses! I did find the inspection from last year when we bought the house last November and the flues were stated to be a 8 x 13 and 13 x 13. Does this mean a oval pre insulated liner such as Duraliner could be a option for us?
 
Yes oval may work for you. Rockford sells them as do others.
 
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Yes oval may work for you. Rockford sells them as do others.
One more thing to pick your ear on, If these are the only two cracks found in the flue and they are both reachable is putting a sealant on them for this winter realistic then looking into piping in the off season?

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Removing the clay liner is the correct course of action. You can think of all the ways it could be done without removing it but if it’s an 8x8 none of them rank above clay liner breakout.
Not sure if you saw, I did find the inspection from last year when we bought the house last November and the flues were stated to be a 8 x 13 and 13 x 13. Does this mean a oval pre insulated liner such as Duraliner could be a option for us?
Also if these are the only two cracks found in the flue and they are both reachable is putting a sealant on them for this winter realistic then looking into piping in the off season? or is that a no no

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Ya I defiantly need another quote here is what I got back when I asked about the inserts, "Its our company policy to break out flue systems with cracks when they are venting solid burning appliances just in case creosote has gotten behind them. We cant leave any fire hazards behind when we do our work."
 
Ya I defiantly need another quote here is what I got back when I asked about the inserts, "Its our company policy to break out flue systems with cracks when they are venting solid burning appliances just in case creosote has gotten behind them. We cant leave any fire hazards behind when we do our work."
That's not a bad policy at all honestly
 
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That's not a bad policy at all honestly
My issue is the quote specifically said they needed to remove the flues because the 6” pipe wouldn’t fit but they also did not measure the flue at all in the inspection (I found the sizes on the first inspection), so they were leading me to believe my flues were too small. That policy of not adding liners to damaged flues was no where on the quote.
 
make sure the new liners are insulated.
That inspection looks very thorough. Keep in mind most chimney guys would have low balled a quote for just dropping a bare liner down those damaged and creosote covered clay liners and called it a day.
The inspection you had looks like you had a diligent person do it. Don’t overlook that.
 
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My issue is the quote specifically said they needed to remove the flues because the 6” pipe wouldn’t fit but they also did not measure the flue at all in the inspection (I found the sizes on the first inspection), so they were leading me to believe my flues were too small. That policy of not adding liners to damaged flues was no where on the quote.
I don't measure them no need to I can tell if it's going to fit.