Expert: Bart Ogden - 4/24/2010

Question
I am planning on installing a wood stove in my basement. I am hopeing to purchase the type that has a built in blower that I can tie into the return air plenum of my furnace. My house was built in the sixties and has a masonary chimney thats lined with clay. I have inspected the liner as best as I can and it looks to be in good shape. I also did a smoke test by burning a bunch of paper and cardboard in the access opening at the floor in my basement and did not smell smoke anywhere in the house including the attick. The stack on the wood burner im looking at is six inch and the clay liner in 8" x 8". There is also an exhaust from my natural gas furnace tied into the chimney. I was hoping to core a hole into the chimney in the basement and tie the stack in above where my furnace stack ties in. I have the acceptable clearences from any combustible source where I plan to tie in. I do not plan on running the furnace and the woodburner at the same time so there shouldnt be any issues with to much being vented out at the same time. My question is, is it safe to use that chimney with the clay liner to vent my wood stove or should I install a stainless steel liner? Also how would you recommend tieing the metal stack from my woodburner into the masonary chimney. Would appreciate any info

Answer
Hi Mike,

You can NOT use the same flue to vent a wood burning stove and a furnace.

If you wish to install a wood burning furnace and tie it into your existing duct work, you will need to install a separate chimney system.

Alternatively, you could install a new flue for the furnace and use this flue system AFTER a LEVEL 2 Inspection is completed by a CSIA Certified Chimney Sweep.  A Level 2 inspection involves checking EACH joint on the interior of the flue with a video camera or other means.  EACH joint must be checked when changing fuels in a flue.  If the flue is interior, you must have 2" clearance to all combustibles from the chimney.  If the flue is exterior, you must have 1" clearance to all combustibles from the chimney.

If the flue is defective (broken flue tiles or voids between flue tiles) you will need a UL Listed lining system installed.  A UL Lining system typically, for solid fuel, requires insulation to be installed and for the lining system to be no less in diameter than the outlet of the appliance.  With an 8" x 8" existing flue liner, this will be impossible to achieve, so I would recommend that you simply install a separate, new flue system for this appliance.

I recommend you contact a local CSIA Certified Chimney Sweep to do some on-site diagnosis of your situation and to give you some specific advisement.

You can find a CSIA Certified Chimney Sweep at www.csia.org.

Thanks for using AllExperts.Com and good luck with your project.

Sincerely,
A. Bart Ogden, President
Home Safe Hearth %26 Chimney, Inc.
Wichita, KS
Voice 316-265-9828
Fax 316-265-9890
www.HomeSafeKS.com

CSIA Certified Chimney Sweep #2653
CSIA Certified Dryer Exhaust Technician #10
NFI Certified Wood Specialist
NFI Certified Gas Specialist
NFI Certified Pellet Specialist
NFI Master Hearth Professional
NCSG Technical Advisory Council Member

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