How to extend masonry chimney with 6" liner in it?

I need to extend my masonry chimney that has a 6" flex liner already installed within it. I need to raise the chimney roughly 8 feet because I built a new 2nd floor on my house and need it to be 2 feet above the peak of the roof. I realize the simplest option is probably to pull the existing liner and replace it with one the correct length once the chimney is done. That seems expensive and a waste of a perfectly good existing liner. Can I just add an additional 8' of stainless liner with some type of coupling and then build the new portion of the chimney around the new liner? Does that make sense?

If so I need to find someone that will sell me that short piece of liner and the coupling I'll need. Any ideas online where to find it?

Thanks,
Eric

BrotherBart said:

Pretty much all of the liner peddlers have the piece to fit between two sections of flex. It is female on both ends and you insert it into both sections and secure it with stainless rivets.

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My concern in that type of setup is what happens when things (coming down the liner) meet the lip at the top of the bottom liner? In other words I thought the connector would be female on the top and male on the bottom to allow things to flow down the liner. The way it was always described to me is if we have dripping creosote it flows down the chimney and should not meet any lips on the way down. Thoughts?

Eric

Also do I need to match the brand of connector to the brand of liner or are they interchangable?

So the first type of adapter appers to be this style.

http://hartshearth.com/productcart/pc/viewPrd.asp?idproduct=4019&idcategory=0

The second (which is more like what I was thinking about) is this one.

http://hartshearth.com/productcart/pc/viewPrd.asp?idproduct=3874&idcategory=0

Is this what you're talking about guys?

Eric

Along those same lines, what about something like this? It appears to be a little more problematic in that it restricts the inside diameter a bit.

http://www.ventingpipe.com/simpson-dura-vent-6dfs-fc-6-inch-duraflex-connector/p1023245

Do I need to use an adapter/connector from the same manufacturer?

Eric

Well I found a local chimney/stove shop that sold me 10' of unused/cutoff 6" stainless flex liner and a 2 clamp adapter for $130. I'm all set now. Thanks for the help everyone. It was much easier after I saw some pics of the adapters so I knew what I was looking for when I got to the shop.

jtp10181 said:

It sound like you will be adding the liner and then building the masonry chimney structure up taller as well. As long as the existing chimney is masonry and you continue the masonry up to the top of the new liner this will be fine.

Might have been easier to adapt to Class A pipe... but this will work also.

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Thanks! That's the plan. I would have tried to adapt class A if it was only a single flue chimney, but there is also a smaller clay flue for our oil-burning furnace.

Hogwildz said:

Sure its obvious, but is the addition within 10' of the existing chimney & liner?
I don't think you have to necessarily be 2' higher than the addition roof, unless its within 10' of the chimney.

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Yes, good question though. Addition is 20' wide and chimney goes through the addition so its about 8' from the peak of the roof.