Woodstove Clearances

Started by mgramann, February 14, 2013, 01:01:09 PM

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mgramann

Odd question, but is a human considered a combustible surface?   ;)

We are considering changing the location of our woodstove, centering it in the home.  This prevents having a very tall chimney outside, and ugly bracing associated with it.  It also will lead to better heat distribution, and make use of some otherwise unusable space, as opposed to taking up valuable living space.

Obviously the manufacturers clearance requirements must be followed from any walls, but if a woodstove was positioned against a flat wall, centered between two doorways, do the edges of those doorways need to follow the minimum side clearances for the stove?  The doors themselves don't open towards the stove to violate the clearance rules, but a person walking through the doorway technically could.

I can't seem to find any code regarding this.

MountainDon

I interpret it to mean if there was combustible trim around the door frame, as well as the door itself, that trim/door would have to be at the proper clearance distance. Objects passing through the doorway are temporary so I would not think it means people.
Just because something has been done and has not failed, doesn't mean it is good design.


mgramann

I was finally able to speak with a mechanical inspector for the state.  As long as the stove and floor protection does not intrude into the doorway, and the manufacturer doesn't forbid it, it is fine to do this.

mgramann

Which brings up another question...

This placement puts the chimney output  immediately under the roof peak.  They make a special, very expensive flashing, but from what I have read, this should be avoided.  I plan to install a "chase" where it passes through the second floor which will be about 13ft tall.  Would there be any problem tilting the chimney at a slight angle in this chase so it moves away from the peak?  I suspect this would be much better than installing elbows, and would make chimney cleaning much easier.

MountainDon

I would recommend two 15 degree elbows with whatever length of straight pipe between them is necessary to shift the outlet end over far enough to work. The chimney in our previous home was installed like that. Cleaning was easy with flexible rods for the brush.

Our elbows were in the insulated pipe run in the attic.
Just because something has been done and has not failed, doesn't mean it is good design.


mgramann

Looking at my truss layouts, it would seem this change might need to occur in a visible location, between the stove and the ceiling.  It is less than ideal, but I can't exactly take a sawzall to my  floor trusses.  :) 

flyingvan

That's exactly what I ran into----since my fireplace is centered exacty under the ridge pole, it had to be diverted.  The manufacturer installation instructions spells out what's allowed.  The nice part is, when you box in the chimney out the roof, you can straddle the ridge so no runoff flows downhill to it.  Sounds like you're drafting a good long distance, all on the interior---this is a recipe for a well drafted fireplace.  Two 15 degree turns won't hurt things a bit---just makes sweeping the chimney a little harder.
We used a Bis Nova with the AC (air cooled) chimney so the clearances are only 2".


   I wish I took more pictures, but you can see the offsets here.  THe same chimney chase holds the gravity wall furnae flue as well.


   Here's the chimney chase.  The flue for the furnace is hidden behind it on this side so there are now through-roof projections on the street side
Find what you love and let it kill you.