I had a Jennaire Stove with indoor grill I vented it out the crawlspace to the vertical
exterior wall. I neglected to use flashing on that wall, Long story short Water
made it's way in around that 6 inch vent pipe and rotted 2 joist ends and about 3-4 foot
of Sill Plate...so make sure you use flashing around those exit ports on your vertical walls.