 This is Nate Adams with Energy Smart Home Performance, and I want to show you why you want to do a little bit of testing on a spray foam job when it's done. So I'm in a client home right now. These rim joists were just sprayed yesterday. And at first blush, it looks like a really nice job, and it's pretty typical. This is a tough foundation to do actually back when I was contracting. This is a friend of mine's house, and we did this house. He became a friend through this project, actually. We miss some stuff, frankly. So this is a rubble foundation here, and this is a very tricky thing to deal with. So right up here, there's some spots that got missed, and it's tough to even see that there's a hole there that leaks, but I'll prove it to you. So this is my little smoke stick. Looks very much like a toy, but actually it's kind of made for that. But can you see how the smoke is just blowing away? So I have the blower door in the front door right now. It's sucking air out of the house, so it means that it's sucking air in through any of the leaks, and it's definitely leaking up in this area. Now how that should look is more like this, where the smoke just kind of lazily comes up the top. But as soon as you get it up there, you can see it's blowing around. So there's a leak. I'm going to hit that with some single component spray foam, which is like the great stuff. You can buy any of the big boxes, but we'll get this sealed up in a second, and then double check that it actually is sealed.