Re: SB: Fireplace in Bale Wall

[Speireag Alden <Joshua.M.Alden.91@alum.dartmouth.org>]

Sgrìobh Norbert Senf:

>>Does anyone have experience building a bale wall with a fireplace in
>>it.  The design the owner wants is a fireplace with a window on each
>>side in the gable end wall.  (snip)
>
>When you build a fireplace, you have to follow your local building 
>code. Typically, your firebox needs to be a minimum of 8" thick, 
>with a firebrick liner. In many jurisdictions you have to maintain a 
>4" air space between the back of the fireplace and combustibles. 
>Covering straw with cement does not turn it into a non-combustible. 
>You need the air space no matter what. Filling the space with 
>insulation, for example, doesn't work and creates a fire hazard.

Norbert -

     I remember past posts on the chemical changes which happen in 
cellulose materials subject to persistent heat, and the past 
experience of one poster who had a chimney fire because of faulty 
design where there was no air space.

     Still, it's clear that you can't have a total air space, or there 
would be a four-inch gap between the fire place and the wall through 
which you could see daylight.  Thermally questionable at best.

     So, how do you bridge that necessary four-inch gap?  Can you 
insulate it at all?  Doesn't it constitute a break in the thermal 
envelope?  I'm unclear on the details, clearly.  What exactly butts 
up against the chimbley?

-Speireag.
-- 
Speireag Alden, aka Joshua Macdonald Alden

If the biota, in the course of aeons, has built something we like but 
do not understand, then who but a fool would discard seemingly 
useless parts?  To keep every cog and wheel is the first precaution 
of intelligent tinkering.   -- Aldo Leopold, _A Sand County Almanac_ 

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