Should I line my existing chimney?

[Dano25]

I’d like to put in a small wood stove for a secondary source of heat.

My flue has an inside diameter of 6 1/4”. I snaked my phone down carefully to see how my terra-cotta liner looked.

I would love some opinions on wether or not I should go with a liner.

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[Sodbuster]

I think you'll have a hell of a time getting a 6" chimney liner down that flue, 5-1/2" maybe doable.

 

[zig]

You may get a 5 1/2 liner to work but no way to insulate it and you need insulation with terra-cotta.

 

[Nick Mystic]

I'm not an expert on evaluating the soundness of a terracotta liner like yours by viewing a camera inspection run, but I can tell you that such a flue can work fine. In our house we have two stoves: one with a 6" ss flex liner inside a large tile liner and the other running straight through an 8" x 11" clay tile liner like yours. The Woodstock Classic is tied into the clay liner through a thimble and it drafts great and stays nice and clean. I think the expansion and contraction of the liner must flake off the ash and creosote because all I have to do is scoop it out of a clean out area below the thimble once a year.

 

[double-d]

When you say a small wood stove, what is the exhaust size off the stove?
Is this stove venting through a Thimble hole or is there a fireplace opening?
I did not notice any cracked tiles, but there appeared to be missing mortar between some of the clay tiles.
Without knowing if you have the correct Code clearance requirements to combustibles, you definitely need a liner and probably are going to need 1/2" insulation around the liner.
Unless you break out the clay tiles, I do not see any way to install an insulated liner.

 

[Dano25]

Thanks for all the replies!

Definitely not even going to try a 6” liner because it’s not a straight shot to the firebox.

6” exhaust Stove will vent through fireplace opening.

Flue is insulated by chimney with brick and mortar (does that count)?

 

[Doc C]

Thanks for all the replies!

Definitely not even going to try a 6” liner because it’s not a straight shot to the firebox.

6” exhaust Stove will vent through fireplace opening.

Flue is insulated by chimney with brick and mortar (does that count)?

No. Needs air space between terra cotta liner and brick. Sometimes you can look up from the clean out and see an air space. Alot of times the Mason slugged the air space full of mortar while building and heat can transfer right through. Also do you have an air space between your chimney and the surrounding combustibles?

 

[bholler]

Thanks for all the replies!

Definitely not even going to try a 6” liner because it’s not a straight shot to the firebox.

6” exhaust Stove will vent through fireplace opening.

Flue is insulated by chimney with brick and mortar (does that count)?

Is this going into a fireplace??? If so you need a liner. Even if not i see missing mortar and a badly offset joint. It should be lined. To go without insulation on the liner you need to have proper clearances to combustibles. Which means for an external chimney you need to have one inch of clearance from the outside of the masonry structure of the chimney to any combustible material. It is 2" for an internal one. Having those clearances is very uncommon. And for your flue to get insulation in there you will probably need to remove the old clay liners.

 

[Dano25]

No. Needs air space between terra cotta liner and brick. Sometimes you can look up from the clean out and see an air space. Alot of times the Mason slugged the air space full of mortar while building and heat can transfer right through. Also do you have an air space between your chimney and the surrounding combustibles?

I do have a air space between chimney & surrounding combustibles. No air space between terra cotta and brick.

 

[Dano25]

With a 6 and 1/4” diameter what are my options for a liner?

Has anyone ever used the liners from tineywoodstoves.com https://www.tinywoodstove.com/product-category/5in-flue-parts/

 

[Doc C]

I do have a air space between chimney & surrounding combustibles. No air space between terra cotta and brick.

Bholler covered all the key points that I would follow if I was in your situation.

 

[bholler]

With a 6 and 1/4” diameter what are my options for a liner?

Has anyone ever used the liners from tineywoodstoves.com https://www.tinywoodstove.com/product-category/5in-flue-parts/

To get an insulated liner in there with that offset joint if those tiles are 6.25 inside you would have to go smaller than 5". Which 5.5" is the minimum for just about any modern wood stove. What stove are you considering?

 

[Doc C]

https://www.hearth.com/talk/threads/tiny-wood-stove-in-a-tiny-house-confirming-issues.164444/

This is a thread we had going a little while back. It shows the quality of some of the tiny home chimney systems. I would steer clear if your link is anything like this company.

Also....and here's the key point. I don't think you will be happy with a 5" liner for a 6" stove. Maybe some folks here have tried it but the numbers do not look good.

I think you are going to have break out the liner. If your doing it yourself...might be just as easy to tear down the whole chimney and just use pipe without the masonry at all.

 

[bholler]

And just order a liner from a chimney company. I have seen some really shady stuff done by and sold by tiny home guys.

 

[Dano25]

To get an insulated liner in there with that offset joint if those tiles are 6.25 inside you would have to go smaller than 5". Which 5.5" is the minimum for just about any modern wood stove. What stove are you considering?

I haven’t gotten set on a stove yet I am just trying to figure out the venting situation first without breaking the bank. Luckily my home is only 1300 square feet, single level and already has central heat. Living room is about 300 square feet with French doors. I Would like something with a larger glass door.