Thank you for the advice in advance. I have a 1 1/2 story home with a central chimney that has two flues installed. The main level has a gas log fireplace and the other flue runs to the basement where there are concrete footings from floor to ceiling underneath the main level fireplace to support the weight of the stone and hearth above. The flue that runs to the basement is a 5" inner diameter with an air-cooled outer diameter of 7". I am assuming this runs to the top of the chimney 35' up. I was hoping to install a wood-burning fireplace in the basement; however, it looks like this will require an 8" insulated flue at the least and more likely a 10" ID insulated flue with the size of fireplace we would like to use.
My question is - how hard is it to exchange the 5" ID for a 10" ID insulated flue? It appears that the opening in the chimney is at least 12" for this flue. Who would be best to do the job if I need help? thanks again