Strangely (at least to my eyes) the last 2 pellet stoves I looked at during installation, required window and vent distances per the UPC or IPC and clearances from the framing members at the point of penetration, and weren't required to clear the roof, only be 12" above grade. I have only seen one basement in my area and it was 50 years old when I was 10, so I am looking at the rest of that assemebly and wondering whether or not it is weather-proof.