How many of you guys are running uninsulated liners

[AngelesCrest]

I'm planning to install my insert myself. I have a 16' exterior chimney. The flue tiles are too small for an insulated flex liner. I don't really want to bust out the flue tiles, but the only way to get an insulated liner in there is to bust them out. How bad is it to install an uninsulated flex liner on a cat stove?

 

[bholler]

I'm planning to install my insert myself. I have a 16' exterior chimney. The flue tiles are too small for an insulated flex liner. I don't really want to bust out the flue tiles, but the only way to get an insulated liner in there is to bust them out. How bad is it to install an uninsulated flex liner on a cat stove?

Do you have the required clearances between the outside of the masonry structure and any combustible materials? If not you are required to use insulation.

 

[AngelesCrest]

I would assume so. The old homeowners had an old smoky insert in there that they just ran directly into the flue with no liner.

 

[bholler]

I would assume so. The old homeowners had an old smoky insert in there that they just ran directly into the flue with no liner.

I would not assume that in my experince of inspecting a couple hundred chimneys a year proper clearances are pretty rare. Just because it hasnt burnt the house down yet doesnt mean it wont ever.

 

[Nick Mystic]

My chimney is in the center of the house and contains three terracotta flues. It is a full masonry structure measuring 8 feet by 4 feet and extends from the lower level of our home through the main level containing a 16' cathedral ceiling. I installed an uninsulated flex liner for my Jotul F600 located on the main level of the house (as viewed in my avatar). I had plenty of room to insulate the liner when I did my install, but I intentionally wanted to leave it without insulation so that I could get some heat from the flue to warm the large thermal mass of my chimney so I could get a slow release of heat throughout the night. It has worked out great. In your case with an exterior chimney your lost heat will heat the outdoors, so you won't experience the same advantage I do.

 

[saewoody]

My liner is uninsulated. The install had to be permitted, and it was passed with no issues by the building inspector and fire marshal. I have an exterior brick chimney with a clay tile lining.


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[Charles1981]

So I have an interior chimney. Its about a 12 inch flu. You could drop a bowling ball down it and it wouldn't touch the sides.

I had an un-insulated liner installed.

The stove store inspected the chimney, The stove installer inspected the chimney (liscensed), then a liscensed sweep cleaned the chimney at both their requests. Then the installer installed the uninsulated liner. Had the sweep come out and clean the liner once a year no problems for 3 years.

Well in year 4, we had a chimney fire....outside the liner. The original sweep failed to mention that while he cleaned the clay flue he left behind large amounts of pyrolyzed creosote that couldn't be cleaned out with just a brush and didn't mention or offer someone else to clean it mechanically with chains and chemicals. Eventually that uninsulated liner acted like an easy bake oven and lit a bit on fire...outside the liner.. (but only after 4 years of use) So failure on many levels all along the way. I even asked the installer to install one at the beginning and he insisted it wasn't necessary.

Long story short, Installer removed the liner. I paid a new sweep 600$ to mechanically and chemically remove the creosote, and the Installer had to install a brand new insulated liner.

Major headache for everyone.

And even though the we have an interior chimney I can tell you that the draft has improved when the rear of the stove is closed in cat mode and the stove has been running much better with the insulation than it did without.

I am also positive that while I was unaware of the creosote left behind from the previous owners using a direct vent setup, and paying a sweep to "clean" the chimney and everyone giving it a green light...it still failed...If we had an insulated liner from the start I highly suspect everything would have been kosher. All that creosote was about 4 inches away from the liner and the insulation likely would have prevented it from combusting. That said we do now have peace of mind that all the creosote was removed and we have a new insulated liner.

Anyway. Do what you can to get it insulated....Maybe look into pour in vermiculite? I don't know if that works in your setup or not....

But get it insulated somehow some way... even if it is more work/ pain in the behind.

 

[bholler]

Yes an uninsulated liner will work yes it will probably pass inspection but that does not mean it will work as well as it could or that it as safe as it could be. It doesn't even mean it meets code just that it passed inspection.

 

[saewoody]

Well, unfortunately for me, the install was done before I stumbled upon this forum. Knowing what I know now, I would have done things differently. I was basing my decisions on the recommendations of the dealer; as I’m sure many first time stove buyers do, which is really too bad. You think are asking all the right questions, only to discover later on that you didn’t really know what the right questions were.


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[Ctstove84]

My pipe is also uninsulated.its a straight shot up about 23 feet.its centrally located and have had no problems with it.the walls in my upstairs bedroom where the chimney goes up are warm to the touch and add some warmth to to the room.depends maybe on where the stove is located ?

 

[blacktail]

My liner is uninsulated. I didn't know anything about insulation at the time and just had the dealer install everything. My tube stove runs fine on it but if I was doing it over I'd go with insulation. No reason not to and it can only improve things in terms of safety and performance. From what I've read about cat stoves, their exhaust runs cooler so I'd definitely go insulated there.

 

[Mike508]

Uninsulated, 6" liner, 22 ft exterior, clay lined chimney. I had 3 people come out, and no one wanted to do an insulated liner. All 3 said it was not needed, and only one was willing to even give me a quote (extra $1200). I even went as far to ask neighbors who have stoves. All had used one of the installers that I had visit. I called the city inspection and they acted like I was speaking Greek. The city came out and inspected and gave everything the green light. So far the insert (standard wood burning, EPA, tube insert) works great. I have measured the temp of the outside chimney after burning 24 hours (from top to bottom with my IR gun) and the brick all reads within 5 degrees of ambient. I read it was "recommended" for the cat stove I wanted (blaze king) but the manufactures of all the tube stoves that I found never mention it. I can update this post over the summer when I have the liner cleaned if anything comes up. I was glad that these forums made me an informed consumer, but I also had to weigh the information of the installers and neighbors.

 

[3fordasho]

When I bought my place in 2014 I had the fireplace and flue inspected (heatilator in exterior masonry structure) and while I agreed with the recommendation to discontinue use of the heatilator and install either an insert or free standing woodstove the guy insisted that an un-insulated liner was the way to go and basically would not install a insulated liner. A second stove shop had the same recommendation. Neither one could know if the masonry structure has the required 1" clearance to combustibles and I don't either. Both acted like I was nuts for asking for a insulated liner. I ended up buying and installing my own insulated liner as I was lucky to have 10X10" inside clay liner so plenty of room for the extra diameter the insulation adds.

Uninsulated, 6" liner, 22 ft exterior, clay lined chimney. I had 3 people come out, and no one wanted to do an insulated liner. All 3 said it was not needed, and only one was willing to even give me a quote (extra $1200). I even went as far to ask neighbors who have stoves. All had used one of the installers that I had visit. I called the city inspection and they acted like I was speaking Greek. The city came out and inspected and gave everything the green light. So far the insert (standard wood burning, EPA, tube insert) works great. I have measured the temp of the outside chimney after burning 24 hours (from top to bottom with my IR gun) and the brick all reads within 5 degrees of ambient. I read it was "recommended" for the cat stove I wanted (blaze king) but the manufactures of all the tube stoves that I found never mention it. I can update this post over the summer when I have the liner cleaned if anything comes up. I was glad that these forums made me an informed consumer, but I also had to weigh the information of the installers and neighbors.

 

[black smoke signals]

NON Insulated in mine bk dealer in early fall 2016 said I didn't need it as per manual not sure if dealer was correct.Later in 16-or 17 this manual was updated to Insulated liners recommended from bk..

 

[fire_man]

An insulated liner is kind of like an insurance policy with the added benefits of improved performance. You hope you never need the added protection it offers, but if you ever hear the sound of a chimney fire, you will be glad you had an insulated liner in there. Even with a massive masonry chimney, its important.

This is from CSIA.ORG

The Effect of a Chimney Fire on Your Chimney

Masonry Chimneys
When a chimney fire occurs in a masonry chimney – whether the flue is an older, unlined type or tile lined to meet current safety codes – the high temperatures at which they burn (around 2000°F) can “melt mortar, crack tiles, cause liners to collapse and damage the outer masonry material”. Most often, thermal shock occurs and tiles crack and mortar is displaced, which provides a pathway for flames to reach the combustible wood frame of the house.

 

[AngelesCrest]

One thing I am worried about is the level of thick creosote inside my smoke chamber. The house, built in the 70s had the previous owners burning who knows what. I had the chimney cleaned but they were unable to get the 1/4” thick creosote off. But the only way to get an insulated liner in there is to bust out the clay liner. Not a win win in my book.

 

[fire_man]

Can you ovalize the liner to fit and insulate? I did that in mine and it worked out great.

 

[bholler]

One thing I am worried about is the level of thick creosote inside my smoke chamber. The house, built in the 70s had the previous owners burning who knows what. I had the chimney cleaned but they were unable to get the 1/4” thick creosote off. But the only way to get an insulated liner in there is to bust out the clay liner. Not a win win in my book.

It needs to be cleaned better than that regardless of the insulation.

 

[Charles1981]

One thing I am worried about is the level of thick creosote inside my smoke chamber. The house, built in the 70s had the previous owners burning who knows what. I had the chimney cleaned but they were unable to get the 1/4” thick creosote off. But the only way to get an insulated liner in there is to bust out the clay liner. Not a win win in my book.

This is almost a repeat of my story. 1/4 inch of creosote they can't get off? That's pure fuel that if it burns is going to cause a chimney fire. It sound like you need to knock out the clay tiles and make sure the smoke chamber is cleaned properly and have an insulated liner. Take it from someone who already almost had their house burn down...

 

[AngelesCrest]

They beat the smoke chamber with chains for a while. Wouldnt come off. Cost me $190 and he said that they couldn’t get any more off. What should I do?

 

[Charles1981]

I had it chemically cleaned as well. Not sure what the stuff was but it kind of melted dissolved the creosote. It smelled real bad for days....but It took care of what the chains couldn't.