Question: I have a 100 year old chimney that hasn't been used in 50. It's actually structurally sound, but most likely unsafe for burning anything. It currently is divided only at the bottom into a coal burning front, and a wood burning rear. Structurally I can, and want to, remove the dividing wall. However, the chimney still needs to be lined. It is straight up, with no diversions. I will be going with gas logs. 1. What's the best product, etc? 2. I've seen the steel pipe, easy to install, etc. but how does it attach at the base? Just brick anchors and grout? Answer: Yours is a sort of custom job. We've made up sheet metal plate (could be stainless or galvanized) to fit across the area above the fireplace opening, then cut a hole in this to receive the liner. You will have to be careful about chimney capacity....two open sides of a fireplace require a large amount of draft to assure they will not leak into the home. See the article on chimney capacities at https://www.hearth.com/what/specific.html. My guess is that you'll need at least a 10" diameter liner and perhaps a 12". One company (homesavers) listed on the HearthNet products page at https://www.hearth.com/prod.html makes rectangular liners that help the chimney retain as much of its former capacity as possible.