Hi , I have an 80 year old home with a masonry fireplace. the masonry extends to the basement as well and has an 8 inch hole which to me looks like a hole for a wood stove it. I stuffed a piece of newspaper in it and lit it to see if the smoke would go up and not into my basement, it did go up! While the newspaper was lit I looked inside the best I could and looks like it has never been used. I want to hook up and old wood stove to it.What are my concerns and can I have fires in both the stove and in the main fireplace on main floor?