Q&A Wall Penetration

QandA Posted By QandA, Nov 18, 2007 at 12:04 AM

Thread Status:
Not open for further replies.
  1. QandA

    New Member 2.
    Staff Member

    Nov 27, 2012

    1. I need to make a wall penetration for a wood stove in my basement. It will be 6" flue in a Type 2 installation. I have reviewed the Southern Building Code (I live in GA.) and I am wondering why it requires a 9" airspace to combustibles for making a penetration with a Class A chimney section that is listed for 2" clearance to combustibles?
    2. I have double (side by side) 2"X4" studs on 16" centers, this leaves 13" total from stud to stud. With a 8" O.D. Class A section, I have 2.5" to either stud. Since I don't have 9" clearance what can I do, short of cutting out a stud and installing a head brace (this is a load bearing wall), to comply with the code? Note: This is not a typical Type 2 installation. I want to use the 6" I.D. Class A for the wall penetration because I need to run about 2.5' outside the wall to clear the bottom of an elevated deck and reach the Tee and the chimney, all of which will be externally mounted to my existing chimney framing/housing that serves an upstairs fireplace. The code gives only one other option which calls for using a larger Class A section to surround a single wall connector, I cannot comply with the clearances for this option either.
    3. Is there another qualified combination? That is, can I put a 10" or 12" single wall galvanized liner around the Class A (8" O.D.) to provide a code adequate barrier? This would provide a total of 2.5" clearance to the studs with a single wall liner either 1" or 2" from the outside surface of the Class A section.
    4. I have not seen a manufactured wall penetration that provides this function. Does anyone manufacture a listed penetration that will take me from a single or double wall connector, through the wall and to horizontal 6" Class A chimney on the outside?


    I think there are manufactured wall penetrations that do the job. Try the folks at http://heatfab.com -

    The reason for #1 above is that insulated chimney is listed for the 2" clearance when it is installed with a complete system. This allows air flow and heat exchange among the matched components. When you install it as a thimble, it has no chance to move the heat elsewhere so more will build up.

    Link: Heat-Fab - Wall penetrations and more...
Thread Status:
Not open for further replies.

Share This Page