I have a masonry chimney about 24"x24" with a clay liner running down it. I measured the clay at around 8 x 13 exterior OD. It is an exterior chimney and when I pulled a piece of flashing off the side of where the chimney meets the house It has a 1" gap from the chimney to the siding. Even though I think I have the right clearances to run a un-insulated liner, I like the idea of it being insulated but do not think it will fit.. I did find on Rockford chimney supply they sell a 1/4" insulation wrap that would only increase the liner OD by 3/4". This liner should work right? I do not think an oval liner is an option because I am going into the chimney from the side and don't see how the tee would work. The reason for the side entry is that I built and alcove adjacent to the chimney where the stove will be.