Mine is a very old, by CA standards, place. I've found newspapers from 1880's in the attic. Starting a re-model of the place for new Kitchen and bathrooms and opening up the floor plan, so the old petrified stone chimney and brick topper had to come down. When I bought the place a few years ago there was all ready an 8" oval Dura-liner system in place. I used to represent Dura-vent back in the 80's when they first introduced the product and have always liked the it. I disconnected the Encore and pulled the DL up and out for future use, maybe at my daughters house . It is in excellent condition....except for the 3/4" screws the meatheads used in putting it together, thereby penetrating the interior liner. It really isn't hard to do it the right way, especially when the manuf sends the right screws with the pipe. Oh well, meatheads!