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Splitting a large clay chimney flue

block2s

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Joined
Nov 13, 2025
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I am working on a big masonry project and I have a large fireplace opening that is 48" by 30". This size means the chimney flue should be about 16x16". But those sizes are too big for the damper and chimney pots I really want to use. So I had an idea to make it work.

Can I run the 15-inch round clay flue liner up and then split it into two smaller 12" or 10" round liners without hurting the chimney's performance? I need to know if splitting it like this will still draw correctly. And if it is okay to do, does anyone know where I can find clay chimney pieces that let you split a large flue into two smaller ones? I have only found stainless steel splitting pieces but I would really like to use clay for the entire structure. Thank you.
 
Not my main expertise though but I think splitting the two would not be as effective coz you're creating 2 cooling down exhaust. I don't personally approve of it. Curious what others think.
 
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