I am renovating a cabin and want to include a woodburning stove. I haven’t covered the
framing yet. Please suggest some assemblies that will reduce the clearances from the
code mandated 18 inches to the wall. Also I am using an existing masonry chimney, formerly used for an oil furnace as my chimney. A mason has verified it’s suitableness.
What is the interior detail where the chimney penetrates the drywall ceiling in order to maintain the 2″ clearance to combustible materials?
Thanks
Replies
covering the wood framing with cement board will reduce clearances.Be sure to check local codes.
To construct a wall that will allow reduced clearances requires a non-combustible surface or wall spaced out a minimum of 1" from the wall behind it. The air space must have openings at the bottom and top to allow free airflow behind the non-combustible wall. If using a non-combustible surface (ie: cement board, the supports for the surface must also be non-conbustible)
Just how much you can decrease clearances depends on the stove itself.
Chimney clearances usually are developed by using manufactured ceiling boxes or wall boxes that are supplied by the chimney manufacturer. All metal chimneys are systems and you must use the appropriate parts for that system to ensure it works safely and correctly.
Find out which chimney system you want to or need to use with your stove and get on the web site for that product and look at the installation pdf's and part pdf's
Your code mandates a clearance? Our woodstoves have labels on them that show specific clearances that vary depending on the model. Thats what the inspectors go by. My regency stove is 5" from the drywall at the back.
thanks,I'll check stove and if no sticker, I'll check manufacturer.ken
As pointed out, the stove literature has clearances in it. I also have a Regency. The baffle at back and sides provide the air spaces built in. The manual says for close clearance the pipe must be double walled (the outer serves as a radiation shield for the inner). The manual also will describe chimney requirements as it passes through the ceiling and attic space, as well as elbow aspects and entry into existing masonry chimney. Manuals from chimney vendors provide this info. I've seen it online.
In my case, I reused some insulated chimney from a former oil furnace installation, from ceiling on up, but it is 7", and the stove outlet is 6". I couldn't get a double-wall 6 to 8 reducer, so I used a single-walled reducer and hung a foot long piece of single-wall 10" from the bottom of the insulated pipe onto which the reducer goes, to provide the radiation shield over that part. Wall behind the stove and pipe is pine T-G panel. When the stove is burning, the wood gets quite warm, but not so that I can't keep my hand on it. I also bought a metal trim piece for where the pipe goes through the ceiling. It is a circular plate, black finish, about 18" diameter, that fits tightly around the chimney piece.
In many places, the local fire department will make a curtesy check of the final installation. It's in their interest to see it done right also.
Regencys are great stoves. We have frequent power outages lasting several days, and as you say, despite being top being hot enough to cook on, the drywall behind is only warm to the touch.
The local inspectors carry mirrors to read the labels on installed stoves because they are too tight to the wall to get your head in.