How to extend a chimney

[bassmaster17327]

I have a clay liner chimney that is 8x8, when the addition was put on the house it was built higher than the chimney. How can I make the chimey four feet taller without putting a liner down the whole thing? I did not know if they made somthing that would clamp on the clay liner and let me attach a couple sections opf stainless pipe

Thanks for the help

 

[DAKSY]

There are adapters out there, but they're used to connect SS chimney liners to Class A
chimney sections at the top of the flue tile, & extend the chimney like you want to do.
I suppose you could simply use the adapter without having the liner attached to the
bottom of it, but I won't tell you you CAN do that & still meet code.

 

[double-d]

Are you venting a stove or is this for your fireplace? Just trying to find out if the 8x8 can be downsized or not. Is the addition withinn 10' of the chimney and having draft problems?

 

[bassmaster17327]

It is for a woodstove, a Quad Isle Royale. The addition is about 6 feet from the chimney, I do not think it is drafting very well. When I start the Isle Royale I have to keep the door open for about thirty minutes, if I close the door to soon it fills with smoke and goes out even with all the air control open. I also get smoke in the house when I open the door. I am new to woodstoves and this one is in my cabin so I have only gotten to use it when I installed it over Christmas so I am just guessing that I have a draft problem. Also I read on here that with not fire going you should be able to put your hand in the firebox and feel the air sucking out, mine seemed like air was blowiing down the chimney

 

[burleymike]

I would go get some 8x8 flue tiles and extend it up. I had to get 3 tiles to make my chimney the minimum height for my new insert. I do have a stainless liner running through the whole chimney though. I also took a piece of angle iron and used tap con screws to fasten it to each tile just to be safe.

 

[bassmaster17327]

I had thought about the flue tiles but I thought I would have to lay brick around the outside for support, the metal pieces and tapcon screws are a good idea. Did you have any trouble with the screws spitting the tiles? Do I have to put morter or anything between the pieces where they meet?

Thanks for all the help

 

[webbie]

How about those things I invented...I can put you in touch with the guy I sold the company to...
http://www.extendaflue.com/cast.html

 

[burleymike]

I put mortar between the joints as well as the angle. I used a hammer drill for the first 3/4 of the hole then switched the hammer off and just drilled the rest. I did not have any problem with the tiles cracking. I will probably run the brick the rest of the way up someday when I have the time.

 

[bassmaster17327]

That sounds like an easy fix to the problem, do you happen to know of a place online that sells the clay liner?

I checked that extend a flue website and it looks like they only have 36 inch extension for 8x8 and that is not high enough for me. They do look really nice though

 

[webbie]

That's bad advice - to extend with flue tiles - You can't use freestanding clay tiles to extend a chimney. You also definitely cannot ship them - they crack even on the way home in the back of your car from the masonry yard.

If I had to make up a temporary extension - although it would not pass any code - I'd use stainless steel rigid liner (maybe 7") which would usually fit tightly down into the existing flue - and then rivet two 4 foot sections together - maybe slide it a foot or more down and pack cement around it. Then it still is too cold, so it should be encased in another pipe - ideally wrapped in insulation also.

There are things called "masonry adapters" which can be used to convert to insulated chimney - but you have to properly support the new metal chimney up there!

Good Luck.