woodstove chimney specs...Hmmmm

...from the National AG Safety Database...

"HOW DO YOU RUN A STOVEPIPE THROUGH A COMBUSTIBLE WALL OR CEILING?

You don't. But if absolutely necessary, the following are approved methods:

• Build a 3.5-inch thick brick masonry wall framed into the combustible wall, with a 12-inch minimum clearance from the clay liner to combustibles.
• Use a solid, insulated, listed factory-built chimney, with a 9-inch air space to combustibles.
• Use a 24-gauge sheet-steel chimney connector with ventilated thimble, plus 6 inches of glass fiber insulation.
• Use a solid, insulated, listed factory-built chimney over a 24-gauge chimney connector, with 1 inch of air space, plus 2 inches from outer wall of chimney section and combustibles.

Connectors must also maintain a pitch of at least 1/4 inch per foot from the appliance to the chimney. Avoid sharp turns, which create excessive resistance to the flow of flue gases, and support and fasten securely with sheet-metal screws, rivets, or other approved means."