Expert: Randy Brooks - 10/3/2009

Question
We were just given a wood burning stove and were going to insert it into our existing (already cleaned and ready to go) brick fireplace. A friend who also has two wood burning stoves was going to install it for us, but we needed to get the 6" stainless steel chimney to go through the damper and up the chimney flue. A store suggested to extend the 20+foot stainless steel chimney to the top of our centrally located existing chimney. Our experienced friend, on the other hand, said that much of stainless steel chimney was not necessary. He only put the stainless steel chimney about 10 feet up the existing chimney. Give the cost of the stainless steel pipe at $25/foot, an extra 15 feet of pipe is a substantial cost. What do you recommend? What are the pros and cons of not extending the stainless steel chimney pipe all the way to the top of the existing chimney flue?
Thank you very much for your input!!!

Answer
Susan,

Thanks for asking. The cons for not extending the liner to the top are plenty. The six inch carries the flue gas temperature to the much larger flue of the old chimney and the stall that occurs due to this vast difference in temperature is the cause of much creosote build up. That brings us to the other point, you will require regular service for removal of creosote from your system, how do you accomplish this with a six inch pipe and the old flue? the creosote removed from the old flue will fall around the six inch and all over the top of your stove. The glaze build up that occurs within your system with type of install is like enamel and will not easily remove with brushing. This material is quite flammable and may result in a fire.

The pros are that this six inch diameter was and is the intended size of the flue for this appliance. the stove will be much more effective and service will be easier and more complete. I would recommend having your existing system inspected to the NFPA-211 standard, level II before the install and likewise recommend having it installed by a pro. Find an inspector in your area that provides these inspections by using the links at the bottom of my home page at www.brooks-hearth.com. Good luck.