Starting up a new thread on my bay window. Here's a link of mention of it in the leaky shower thread just for reference: https://www.hearth.com/econtent/index.php/forums/viewreply/93476/ Executive Summary While I was blissfully ignorant, one of six bay window sills rotted away before I realized what the crinkling latex paint was trying to tell me (see: photo 1). Then, one morning, after a big cup of joe, I decided to push my finger on that window sill, come what may. Here's what happened (see: photo 2). That's not good! So I whipped out a little saw and did what my gut was telling me I was going to regret (see: photo 3). Holy crap! What's going on in there, and what's he doing in my wall (see: photo 4)? Houston, we have a problem.