Just tearing them out or updating them to a more modern design,....that's why I was asking. If that's what`s there or partially done, then it is what it is, no updating it. A lot of times people will build with certain features when they are not needed for the more modern things, such as water heaters and heaters which use PVC for a flue they are soo efficient, or the newer wood gas reburning stoves which do not need the traditional chimney of masonry.I meant to type I have a couple of questions. It's block because that's what's being used in the project. Do you have any experience in building chimneys?