Mind the Gap at the Rockland Public Library
It's pretty obvious that when we're air sealing, we're closing gaps. What might surprise you is how many gaps there are, all over the most solid of buildings. Gaps between trim and fireplace surrounds or windows:
Even "gaps" that are so big, and go so far, they may as well be portals to another universe:
You can feel the cold air they let in, and infrared analysis will expose them for sure. But once you find them, what will you do about them?