Will 6”insulated liner fit in 8x12 clay chimney

[Rob711]

Currently have uninstalled 6”liner in my exterior masonry chimney connected to my vc intrepid inside fireplace, see avatar.
Going to be doing house Reno requiring extending chimney.
Does insulated liner fit 8x12 clay. I tried searching but couldn’t find answer. Thanks
Rob

 

[brenndatomu]

By the specs yes, an insulated liner should be about 7.5" OD, but in the real world, it will be a challenge for sure...depends on how much the mortar joints are sticking into the flue...and if any of the tiles are offset, etc...in other words, it just depends

 

[begreen]

Unlikely to fit if the ID is 7" x 11", especially if there is mortar ooze between the tiles or any offsets. DuraLiner is pre-insulated and 6 5/8" OD in round. It also comes in oval for this situation which is 7 3/4" x 4 3/4".

 

[double-d]

A standard 6" Flex Liner is 6.25" on the outside. Adding 1/2" insulation, that you install yourself, could add another 1.5", because it "overlaps it's-self" because of its width. If you trim it so its not as wide, and only meets up with it's-self then it would be about 7.25".
Some Pre-Insulated liners can be 7.25", so as others have mentioned, it would not fit into a 7" opening.
But the clay tiles can be broken out / removed, and by do that will leave you with an approximate 8" x 12" opening, and that is very doable to install an insulated liner.

 

[Rob711]

This renovation won't be starting until October/November I'm just trying to have everything I'll need. I've seen some videos of guys ovalizing liners diy that are entertaining. Since the chimney will be extended, a conversation with mason may solve my problems. Perhaps the cost of him knocking out clay, and NOT installing clay liner on the new part will be about even. Thanks, I'll post progress.
Rob