Hi, I have a question about putting a wood stove in my basement. I have a masonry chimney that has two different flues, one for my insert upstairs and this other one that goes down to the basement. It has a 6 inch hole coming into the basement from the flue through the concrete wall that will fit a single wall 6 inch pipe. My problem is that the top of the hole is only 6-7 inches from the finished ceiling, and I think you have to have 18 inches on single wall right? Any suggestions on what I might use to make this work. Thanks.