How to vent wood burner as in insert in existing masonry chimney?

[wcarrico]

I am replacing an old insert that did not have a direct connection to the chimney with a Buck 94nc. My first thought was to install double wall stainless stove pipe up the chimney. There is no clay flue, just straight brick. I have an offset from left to right if you are looking at the stove from the front. My concern now is attaching all the double wall in the masonry chimney and the weight of the pipe on the offset elbows. I am looking for the absolute safest way to vent this stove. That's the whole reason for getting rid of my old insert. I don't want a chimney fire, AGAIN, in this masonry chimney. (Fire was before I bought the house.) I thought this double wall stainless stove pipe would be the safest, but should I consider the flexible liners instead? Besides safety, is one more efficient than the other? Thanks in advance for your suggestions.

 

[begreen]

What's needed is a liner inside the chimney, not double-walled chimney pipe. A flexible liner will be the best to handle the offsets. They make liners in various weights. A medium or heavy weight liner is the best. The liner must be insulated. It's held captive by the top plate which will also support its weight. This method will make it safe for the brick chimney.

 

[wcarrico]

Where is the best place to buy such liners online?

 

[begreen]

It's easy to buy light duty liner online, but harder to get quality medium and heavy duty liner. The best liners are often only sold to professional installers. There are also liners that are better to avoid. 2 ply liners have a tendency to separate or fish mouth inside which renders them defective. There's a bit to learn before DIY. The first thing is that the chimney must be completely cleaned before proceeding. This includes the smokeshelf area.

Here is an example of a good medium weight liner that can be purchased online:

FireFlex 316L Smooth Wall Basic Chimney Liner Kit

Your FireFlex Chimney Liner Kit will include a FireFlex Smooth Wall 316L .011 thick stainless steel liner, 13" x 13" top plate with rain cap and appliance connector for vertical connections.The strongest liner on today's market!

firesidechimneysupply.com

 

[wcarrico]

Is insulating important? I've been looking at the pre insulated liners like this one.
https://www.cheapchimney.com/products/pre-insulated-hybrid-chimney-liner-only?variant=25241906057

 

[begreen]

Insulation is essential, especially in a chimney with no clay tile lining. Not only is it code required, but the flue system will perform draft better and stay cleaner as long as dry wood is burned. One can use preinsulated, or the insulation blanket can be wrapped around the liner. Be careful with kits to get only what you need and plan well.

I haven't heard of Cheap Chimney, their name screams caution, but they may be legit. The website looks freshly made, it's dated 2025. The products listed are good, so due diligence and caveat emptor. If they do turn out to be a good supplier, let us know!
Rockford Chimney is a reliable source:

Pre Insulated Chimney Liner Kit | Insulated Flexible Chimney Liner Kit - Rockford Chimney

Free shipping on Pre Insulated flexible chimney liner kits. The Pre Insulated chimney liner is UL Listed & features 1/2" insulation to keep flue gases hot.

www.rockfordchimneysupply.com

 

[wcarrico]

Any thoughts on poured insulation?