Do Liners Always Need To Be Insulated?

[Mr.B]

First I want to say this forum is great!

So I purchased a Drolet Stove earlier this year to replace an old Morso 1125. The new stove requires a 6" liner which I intend(ed) to installed myself but I didn't realize that the liner needs to be insulated. So my question is does a liner always need to be insulated and judging from the picture I attached do you think an insulated liner will fit without removed the clay tiles. The clay tiles have shifted a little but doesn't look to severe.

Thanks

 

[bholler]

First I want to say this forum is great!

So I purchased a Drolet Stove earlier this year to replace an old Morso 1125. The new stove requires a 6" liner which I intend(ed) to installed myself but I didn't realize that the liner needs to be insulated. So my question is does a liner always need to be insulated and judging from the picture I attached do you think an insulated liner will fit without removed the clay tiles. The clay tiles have shifted a little but doesn't look to severe.

Thanks

An insulated liner will not fit. It is very possible a bare liner won't even fit.

As far as does the liner need insulated there are 2 factors there.

1st is code. To meet code for a chimney venting a solid fuel appliance (which is a class a chimney) a masonry chimney need clearance from the outside of the masonry structure to combustible materials. That clearance is 1" for an external chimney and 2" for an internal one. If you don't have that clearance you need insulation.

2nd is ul listing. Most chimney liners are not tested for use with wood without insulation. So in order to install according to the ul listing for your application (which is required by code) you would need insulation. Unless the liner manufacturer paid to have the liner tested for use in a chimney with proper clearance and no insulation on the liner.

Then you have the practical side. An insulated liner will be safer and will out perform an insulated one in every way.

 

[Riteway]

It might be worth calling Rockford Chimney Supply; they might be able to custom-make something that would work in your situation: https://www.rockfordchimneysupply.c...iner-only/square-chimney-liner-liner-only.php

I was reading through the manual of my recently-purchased Drolet insert, and read that a 5" may be acceptable, but only in Canada. I assumed that's a US vs. Canada code issue.

 

[Hoytman]

If that liner is in good shape I wouldn’t touch it or change it. Put a cap on it to keep moisture out, when it’s cold start small fires in it and warm it up gradually, get it hot and keep it hot, and it’ll last and last. Keep your money in your pocket!

If you want/need optimal performance (draft) out of that chimney then a liner light help you. Insulated would be best if it will fit.

 

[bholler]

If that liner is in good shape I wouldn’t touch it or change it. Put a cap on it to keep moisture out, when it’s cold start small fires in it and warm it up gradually, get it hot and keep it hot, and it’ll last and last. Keep your money in your pocket!

If you want/need optimal performance (draft) out of that chimney then a liner light help you. Insulated would be best if it will fit.

Without the required clearances it is not safe to use as is.

 

[bholler]

The clay tiles will need to be removed in order to install a liner.

 

[Mr.B]

The clay tiles will need to be removed in order to install a liner.

I was leaning towards renting the tools from Rockford to remove the tiles and install an insulated liner.

 

[Hoytman]

How long has that chimney been working like that?


Provided it is sound it will likely repeat it’s years of service several times over if it’s maintained.

Given that picture, lots of chimneys across this land are the same and have worked for decades before codes changed over the last thirty years.

I mentioned nothing of clearances or codes. I just said check it, maintain it, keep your money. Simple as that as an option. Only he can determine to spend his money.

 

[bholler]

I was leaning towards renting the tools from Rockford to remove the tiles and install an insulated liner.

That is the best option.

 

[bholler]

I never mentioned anything about clearances. That’s his job to hire a sweep to determine.

If the chimney has been working for years, regardless whether it meets modern codes, it should easily continue to work. If he changes it, then update it. Easy, peezy.

Unless the wood has pyrolized to the point where it is ready to ignite. Just because nothing has happened yet it no reason to ignore a potential safety issue.

And honestly after inspecting many hundreds of chimneys I can tell you the chances that it has the required clearances are very very low.

 

[Hoytman]

If you change it the best option is to put the liability in the hands of a trusted and reputable sweep. There goes your money, but it comes with peace of mind.

 

[Hoytman]

Do you find wood in everyone you disassemble?

 

[bholler]

Do you find wood in everyone you disassemble?

Not in it but wood is almost always touching it. And usually visibly discolored from heat

 

[Hoytman]

How much wood touching it? Between the brick and the tile?

 

[bholler]

How much wood touching it? Between the brick and the tile?

No not between the brick and the tile. On the outside of the brick. How much varies greatly. Sometimes it is the whole length sometimes it is just at floors. But it is usually touching somewhere

 

[Hoytman]

I’m not seeing how you can tell from that picture it doesn’t meet clearances. Maybe it’s the way the picture shows up in my screen.

You talking about going through rafters and floors?

 

[bholler]

I’m not seeing how you can tell from that picture it doesn’t meet clearances. Maybe it’s the way the picture shows up in my screen.

You talking about going through rafters and floors?

I can't tell from that picture at all. I know from years of experience that the vast majority of chimney are not built with proper clearances.

And yes some are just at rafters and floors. Others are framed in tight the whole way or up against siding on the outside. It varies allot. But there is usually wood touching somewhere it shouldn't be.

 

[Hoytman]

So are you saying there is no way to bring that chimney to code, without using a Insulated SS liner? More specifically, are you saying there is no way, to insulate a clay liner? I’m not asking if it makes sense or is impractical because you prefer SS. Not trying to sound harsh.

 

[Mr.B]

No not between the brick and the tile. On the outside of the brick. How much varies greatly. Sometimes it is the whole length sometimes it is just at floors. But it is usually touching somewhere

If the brick is touching anywhere it is at the roof penetration. There are actually 2 flues, one about 6" x 14 " for a huge fireplace on the first floor and the other from the picture I posted for the wood stove in the basement. The brick is then surrounded by cinder blocks that go from the basement into the attic. Never got a close look at the roof penetration in the attic. That being said according to the installation manual that i just read the flue for the stove i bought can't be any larger in total area than 6" round. But as you mentioned 5" is acceptable in Canada. Ill be calling Drolet on Monday to inquire on the 5" possibility.

 

[bholler]

So are you saying there is no way to bring that chimney to code, without using a Insulated SS liner? More specifically, are you saying there is no way, to insulate a clay liner? I’m not asking if it makes sense or is impractical because you prefer SS.

There is no reasonable way to bring it up to code no. You cannot insulate an existing clay liner. And there is no tested way to do it when new. The only way would be to modify the structure around the chimney to give proper clearances. And then you would still have a clay liner. Which simply does not work as well for wood. And I didn't think you were being harsh or anything. Just asking questions no problem with that at all.

 

[bholler]

If the brick is touching anywhere it is at the roof penetration. There are actually 2 flues, one about 6" x 14 " for a huge fireplace on the first floor and the other from the picture I posted for the wood stove in the basement. The brick is then surrounded by cinder blocks that go from the basement into the attic. Never got a close look at the roof penetration in the attic. That being said according to the installation manual that i just read the flue for the stove i bought can't be any larger in total area than 6" round. But as you mentioned 5" is acceptable in Canada. Ill be calling Drolet on Monday to inquire on the 5" possibility.

In that case the block below would be the masonry structure of the chimney and you would need clearance from that. There really may be enough masonry thickness there that is isn't a safety concern. But it could also only be 4" block with the clay right behind it so no better than a plain brick chimney. There is no way for me to know.

And if 5" is ok for the stove that will probably fit ok. 5.5 probably won't if there are offset joints.

 

[Hoytman]

How can cast-in-place liners pass in an existing brick or block chimney then? I’m not trying to be argumentative. I’m genuinely interested and some of what I read (everywhere...not just your posts) doesn’t add up).

Seems to me that if I had a chimney like that, and I do...same exact liner...and I decided to put in 6” square or round clay tongue-n-groove liners ( what I will use ... Sandkuhl liners), down sizing the liner for better draft, then there would be plenty of room to insulate a clay liner. Never mind long runs that complicate any feline by additional labor.

I realize most sweeps hate clay. I get that. I don’t. I burn coal and wood. I‘ve seen far too many rotted out SS liner pictures from anthracite use...online pictures, and have plenty of coal burning friends recommending against those liners...unless I go with AL29 4-C...some of which swear it’s better than 304 and 316T. I have no clue other than what I’ve read and seen. I’m not taking the chance with spending that kind of money when I’d rather pay the labor costs and be done with the clay and maintain it properly. So that’s why I’m asking. I‘ll keep the chimney as is before I rip it down, or I’ll go with a SS liner if I must, but I don’t want to.

Searching deeply on the internet there are only a few articles that claim clay will outlast SS (if) it’s maintained/used properly and covered.

I’ve talked with a few local sweeps, and when I mention coal, or show them pictures of rotted out liners from anthracite, the response is the same, they have no experience because coal burning has been gone from this country for nearly 70 years now. I figured being from PA you could help me with my idea.

Temoving a large clay liner and going to a smaller round liner should afford plenty of room for loose fill insulation and better yet, wrapping the clay with insulation.

My chimney is only 5 liners y’all and I will be extending by one or two. Maybe one and a pot on top. I’d rather go two full liners. Otherwise my chimney is solid. It’s worked for 60 years. I will be having an inspection done before any construction starts.

 

[bholler]

How can cast-in-place liners pass in an existing brick or block chimney then? I’m not trying to be argumentative. I’m genuinely interested and some of what I read (everywhere...not just your posts) doesn’t add up).

Seems to me that if I had a chimney like that, and I do...same exact liner...and I decided to put in 6” square or round clay tongue-n-groove liners ( what I will use ... Sandkuhl liners), down sizing the liner for better draft, then there would be plenty of room to insulate a clay liner. Never mind long runs that complicate any feline by additional labor.

I realize most sweeps hate clay. I get that. I don’t. I burn coal and wood. I‘ve seen far too many rotted out SS liner pictures from anthracite use...online pictures, and have plenty of coal burning friends recommending against those liners...unless I go with AL29 4-C...some of which swear it’s better than 304 and 316T. I have no clue other than what I’ve read and seen. I’m not taking the chance with spending that kind of money when I’d rather pay the labor costs and be done with the clay and maintain it properly. So that’s why I’m asking. I‘ll keep the chimney as is before I rip it down, or I’ll go with a SS liner if I must, but I don’t want to.

Searching deeply on the internet there are only a few articles that claim clay will outlast SS (if) it’s maintained/used properly and covered.

I’ve talked with a few local sweeps, and when I mention coal, or show them pictures of rotted out liners from anthracite, the response is the same, they have no experience because coal burning has been gone from this country for nearly 70 years now. I figured being from PA you could help me with my idea.

Temoving a large clay liner and going to a smaller round liner should afford plenty of room for loose fill insulation and better yet, wrapping the clay with insulation.

My chimney is only 5 liners y’all and I will be extending by one or two. Maybe one and a pot on top. I’d rather go two full liners. Otherwise my chimney is solid. It’s worked for 60 years. I will be having an inspection done before any construction starts.

For coal yes clay is better. 316 is the best alloy to use here. It holds up ok but I would still go with clay for coal use if possible. I also always use at the very least heavywall flex 316 for coal but prefer rigid 316. Light wall won't last long at all. And they need to be cleaned and oiled at the end of the season.


If someone has designed and tested a listed clay lining system that meets zero clearance requirements that is great but I don't know of it. I also don't know how you would set clay tiles inside and existing chimney

 

[Hoytman]

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Clay Chimney Liner, Clay Flue Liner, Round Flue Liner, Square Flue Liner

Sandkuhl manufacturers clay square flue liners, rectangular flue liners and round flue liners. All clay chimney flue liners meet ASTM.Flue liner offsets, wall thimbles, clay thimbles also available.

www.sandkuhl.com

 

[begreen]

The clay tiles will need to be removed in order to install a liner.

What about installing an insulated, oval liner instead? That is made to solve this issue with the common 7x11" ID tile.