Extending a chimney liner, bust the clay? - help!

[RickBlaine]

Suggestions needed for extending the chimney liner (stove delivery is next week):

I have a short, external brick chimney that I will be running a smooth walled, 6" insulated stainless steel flexible liner through. The distance from top of stove to the very top of that clay flue tile (see photo) is 10 feet. That clay flue tile itself is 12 1/2" tall, 12 1/4 inches square, has a few hairline cracks (please see photo), and sits on top of a concrete chimney cap. No water gets through.

According to the stove manufacturer, I need a minimum of 12 feet of flue liner. Thus, I need to have 2 feet of flue above the top of the clay liner, or if I bust the clay liner up- I will need 3 feet above the concrete chimney cap.

I would like to keep the chimney liner insulated all the way (again, I have a short run and need all the draft help I can get).

What can I do?

Keep the clay: Should I run a flexible liner to a stainless steel clay flue chase cover, transition to a 2 foot stainless steel Class A insulated chimney liner, and then add the rain cap?

Remove the clay: Should I bust the visible clay liner up with a sledge hammer and then install a 3 foot stainless steel Class A insulated chimney liner above the flexible liner? Can I go with a 4 foot pipe? At what point do I need support braces?

Either: Can I run the flexible liner up continuously through a cheap stainless steel liner cover (no transition from flexible to hard).

I don't care what the finished install looks like, just that it drafts well and is something I can do myself to save money
.

I searched and there are only a few threads about transitioning from flex to hard liner. None had a picture of an adapter or how to do it. I know I can't be the first one....

The concrete cap has two exit holes through it (one for fireplace and one for gas furnace). It is 70" by 37"

Thank you! Comments, suggestions, threats welcome!

 

[begreen]

Extendaflue?
www.extendaflue.com

 

[pen]

How about something like this? http://www.cjshearthandhome.com/transition-anchor-plate-ventis-class-a-to-chimney-liner-adapter/

 

[RickBlaine]

The Extendaflue to fit a 12 1/4 inch clay liner will cost me over $1,400. Perhaps there is another solution that will not cost as much?

EDIT: The Extend-A-Flue website has a product called Boost-A-Cap that may work, but there are no height specs listed on their website. I will call them in the morning. Thank you.

 

[RickBlaine]

@pen: That is actually pretty good! Thank you. Looking at their site now....

It seems I would need their proprietary rigid liner and rain cap to easily connect above the transition plate- which is doable. This solution may only add $400 to my liner costs.

Have to research how high I can go above the clay liner before needing a support brace- I would like to avoid that expense if I can. Seems this company sells 2, 3, and 4 foot sections of Class A liner to fit this transition plate.

 

[pen]

You'll have to look at their documentation for use with that top plate. For a standard Class A chimney, a brace is often needed every 5 feet of length.

It might be worth calling a few other suppliers and referencing this piece to see if they offer something similar but don't have it listed on their websites.

I've never dealt with the company I linked to, but this is the only example of this sort of connection that I have been able to find.

 

[pen]

If it were me, and going this route.... If it would be OK for you to use the 4 foot section of class A without needing a brace, that's definitely what I'd want to go with.

The draft is the engine of these things, after going through all that and using a 2 foot section just to find you don't quite have enough draft would be disappointing. It's amazing the positive outcomes I've seen by adding just a few extra feet from people sharing their experiences on here.

 

[RickBlaine]

Yes, good thinking. If I am going to do this extension this way, might as well go with a four foot Class A liner. I don't mind taking it apart to clean when the times come.

I had to go with a smooth walled liner for the increased draft as well. This forum is loaded with good info- one such gem was that a corrugated liner may "cost me" as much as 20% of a draft. I can't imagine that kind of a loss with such a short run as I will have, but every little bit helps.

Thank you sir, from a Blues Brothers fan!

 

[chimneylinerjames]

I would use the transition plate. Break out the flue so you can securely mount the plate to the crown. Then add whatever you need for Class A. I would recommend using 4'. It will only help going taller. And as already mentioned, after 5' you will need additional bracing.

 

[pen]

I would use the transition plate. Break out the flue so you can securely mount the plate to the crown. Then add whatever you need for Class A. I would recommend using 4'. It will only help going taller. And as already mentioned, after 5' you will need additional bracing.

Does the chimneylinerdepot have a similar product? I couldn't find it on the site.

 

[RickBlaine]

James, I suppose the question is, -Can I mount the transition plate to the clay liner (keeping the extra foot of length and negating the concrete work I will have to do if I bust up the clay liner)?

Does Chimney Liner Depot sell, or can fabricate, some such transition plate (to be mounted on the clay flue)?

@pen: we asked at the same time.

 

[chimneylinerjames]

Does Chimney Liner Depot sell, or can fabricate, some such transition plate (to be mounted on the clay flue)?

The best thing is to mount it to the concrete, I cannot guarantee it will not damage the concrete, but most likely it will not. But Chimney Liner Depot can offer something you are looking for.

 

[chimneylinerjames]

Does the chimneylinerdepot have a similar product? I couldn't find it on the site.

We do have them, we do not advertise Class A pipe for the moment. But if you do not see something on www.chimneylinerdepot.com, always call and ask if we can make it or we can atleast order something for you.

 

[pen]

I see this situation get asked about a few times a year and each time I have to dig and dig to find a vendor listing such a product on their website.

I often wonder if more folks would utilize them if they were listed with other adapters and more people know such a product exists.

I certainly would have used one had I known they existed when I lined my chimney.

 

[RickBlaine]

James, thanks for the response. "Why" is it better to mount it to the concrete? Wouldn't I have to make the mounting surface perfectly square and even- attributes that the clay tile liner already has?

Also, other moderators here on this forum have mentioned the 2-ply smooth walled liners and the rare, but frustrating kinks that can develop. One reason why I looked at purchasing your 1-ply smooth walled liner, the Flex King HD....

 

[chimneylinerjames]

It is better because you should use tap cons or other fasteners to hold it down. Think of a heavy pipe on the top of the plate with a rain cap and the wind blowing hard. It could tip over and damage the liner and/or top plate. But if it was screwed to the concrete this will not happen. It cannot be screwed to the flue, it is too fragile.

Yes the 2 ply liners if dented on the outside hard enough can create "fins" on the inside. It is a negative to that liners. The Flex King HD does not have that problem. It is smooth and incredibly strong.

 

[RickBlaine]

Good explanation on the visual using the wind. That clay liner was installed in 1957 and the house is doing fine, but yeah, adding a 4-foot pipe and rain cap may cause trouble.

Tonight I will research the concrete work I will need to do if I go this route. Seems taking a 5 pound sledge to the clay liner should take a few minutes....but must see a video or such as to how I "re-form" an acceptable base...

 

[Xena]

I wouldnt smash it w a sledgehammer you could crack the liner below. Seem to recall some people using a diamond blade on an angle grinder for a clean cut.

 

[chimneylinerjames]

you could crack the liner below

It's ok if the below tiles get damaged, he is installing a liner. But the use of a diamond blade is a good idea.

 

[Xena]

I know he's installing a liner but no reason to be a hack and damage the inside of the chimney.