Help! We bought a 2004 stick built home that came with an all-metal gas log "fireplace" unit, vented with a naked 6" steel pipe, that clears the roofline by about 8 feet outside. The house has siding on it. There is no masonry chimney and from what I can tell, this is just a metal unit, nothing else behind it on the inside. Photos attached. We are wanting to install either a free standing wood stove OR an insert, both of which we have used and maintained before,( but only with existing masonry chimneys and insulated pipe). The pipe is clearly connected to the unit. When we pull out the unit, what are we looking at in regards to making the opening sufficient for an insert or free standing stove? Can we use the existing pipe being as it's clearly uninsulated on the 8 ft clearance outside?