In particular, I was aiming to find out where the water was coming in, what damage the water had done, how to stop the water coming in, and what needed to be done to repair the done damage.
The window is just as much of a mess as we'd thought. The top of the window frame is shot; there were two pieces of wood making up the exterior casing: one sitting horizontally and projecting 2 inches, providing what's nowadays done with an aluminum drip edge. Below that was the flat (relative to the wall) trim, maybe 5 inches wide. Half the drip edge is gone; half of that casing piece is split away, too, and—as you can see in the photo—the split angles back toward the house, funneling rainwater into the window and wall. Oy. Stay tuned for updates on all this, I'm just getting to today's adventure.
As I was up on the ladder, it started to rain. Hey, a great opportunity to see where the water's
going, check out the guttering. I went inside and upstairs to look out the window, to take a picture from above. Here's what I saw:Holy moley. The picture doesn't show it terribly well, but there's a huge spray of water directly against the house. With great vigor. Clogged drain. Clogged drain + water + cold=ice, expanding and splitting the gutter; split gutter plus [still-]clogged drain plus 1" per hour of rain times, oh, 450 sq feet for the half of the roof this is draining, works out to about 18 cubic inches of water per second. Oof.
It's not the leak at the top of the window, but it's certainly not doing anything good for the wall. And it's doing certain not good quickly.
Seamless gutters, anyone? And a big ol' clearing-out of the drainage.