Peter Lohmann shows how French casement windows seal properly: spring-bronze strips interlock between sashes, and a folded bottom piece works with a J-channel to drain water and compress for a tight seal. When the bottom channel gets compressed, the sash won't close fully, but freeing it restores the seal.
Alright, we've got here a bay of casement windows. I'm taking this video for reference to show how the weatherstripping should function when it's installed properly. And this center window here is pretty decent. So the first thing to notice is that there's two strips of spring bronze weatherstripping if I can get the light to cooperate, that run up and down these two faces. And those faces interlock with the other side. There's no weatherstripping here. But on this side, there's two small strips. The painters have sort of painted over it. So it's not functioning properly, it's not springy, but there's a little bit of spring here, you can see. So when these two doors close and interlock, the spring is compressed and provides a seal. You'll also note that there's spring runs all the way around the perimeter, the, the top three sides, and there's a different kind on the bottom. Again, it's lost some of its springiness, but it still pretty much functions. And then the most interesting part is the bottom here. And on the bottom edge of the frame, there's a piece, a thick piece, that's like folded over here. And there's a gap. See the gap? And that interfaces with the bottom of the window here. See how there's like a J-channel and then there's a piece here which moves. And this piece here on top, I can't find this anywhere, so I'm going to have to come up with a different solution. It's got this triangle structure that holds it away from the window and provides a place for the water to go. But when this J-strip interfaces properly with the bottom of the window frame, it works really well and provides a nice tight seal. So I'm going to try and demonstrate that here. See how the window is completely in? There's no give. It's all the way against this bottom edge here, and the J is interlocking completely. See that? And that little piece gets compressed. And you can't really tell from the video, but it has a really nice feel to it. Okay, so you hear that? Nice solid thud as the window seats home. What's been happening is on some of them, it starts working down here as you close the window, and then there's a problem. What ends up happening is people push on this as they look out the window and it gets compressed against the bottom here, and then the window isn't able to fully close. I'll show that over here. So on this window, it starts properly, but then it won't go any further here. See how the window won't close? So the task is to free up this channel which has been compressed. See how there's really no gap there? And that should fix the problem.
