mmcoal wrote:Berlin wrote:12x12 is not ideal, but tell us more. is this an interior or exterior stack? is this stack higher than the highest portion of the home? higher than the highest interior space? what is the overall height from fireplace to crown? pictures help. 12/12 may or may not be a problem based on these other factors. Large flues got a bad rap because in the 50's builders started building stacks on the exterior of the home and built them short, typically on the family room "additions"; this lead to a host of problems expecially when someone slammed a fischer insert into them. with coal and a proper chimney a lot of the oversize flue concerns don't apply. I'm not a fan of making the opening at the top smaller, in my opinion this doesn't help anything and may lead to potentially dangerous problems. tell us more about your stack.
This is an exterior chimney about 20' high. Being an older house the chimney wasn't built quite as tall as it should be, but is actually taller than the peak of the roof.
In keeping w/ NOT using a Stainless Steel Liner solution...this video shows a very clever method to end up w/ a clay liner, provided it is large enough to accommodate proper size liner and it is a straight chimney run. This is way more economical than any S.S. liner, easily done by the DIY'er and will last forever.