Four Dumb Roofing Mistakes means One BIG Roofing Leak

This video, by Marc and Mitchell from High Quality Home Maintenance, in Cedar Rapids, Iowa, details some common roofing mistakes: lazy step flashing, lazy roof-to-wall flashing, lazy nailing, and general laziness. It doesn't matter if 99% of the roof is perfect if the flashing doesn't work. As it turns out, ProTradeCraft has an animation showing correct dormer flashing installation.

TRANSCRIPT:

Situation normal. Maintenance situation. They’ve had a leak along this dormer inside for 10 to 20 years. I started up here thinking, I’m going to just make sure. As you can see, water’s been here.

A likely roof leak: where the dorner roof meets the main roof

If I had to guess, a little bit of water’s been getting in right there, because when water gets backed up, that’s what happens—it’ll leave this dirt trail. So, we’re going to redo all this flashing, take all this siding off. We’re taking the shingles off now, and we’re going to take care of this problem today—hopefully in one day.

Don't butt shingles near step flashing

Okay. No-no number two: you never want a butt joint this close to the edge of a flashing. Because if water’s getting in here—and it will—it’s going to migrate. It wants to get over here, and you can even see it’s been getting in up here. This has been leaking up here, and that’s no-no number two.

Step flashing needs a vertical leg

No-no number three: I just took that shingle out and thought, well, let’s see. That step flashing doesn’t have a vertical leg—that’s not going to help anything.

Okay, so this one is trying to do something; it’s curled up. We’re going to end up taking this fascia off and redoing that. And we have no-no number four.

I just took out—which one? This one? That one? No, I think it was this one. I just took this one out. Okay, that one was up in there trapping water on a seam. This is a joint right here, so water’s been getting in here the entire time—right in there. Can’t see it—that’s a nail turned sideways.

Roofing nails should be installed flat

So, this is the nail head under the ice and water that’s been leaking ever since. Okay, so we got one layer of flashing out. This is a second layer of step flashing, because two layers of step flashing will definitely keep it out once the first one fails. And then you ice and water everything. That’s when I know I’ve got some real professionals here. Sarcasm. Sarcasm.

Headwall flashing goes ON TOP of the shingles

Okay, we’re still on this job—still doing the tear-off portion of it. Here’s your beauty row. They call this the beauty row so you don’t see the flashing. Well, you took the ice and water and you put it on top of the flashing. Then you stopped it here.

There’s the headwall flashing. Go ahead and cut this—let’s verify that’s the headwall flashing. Well, that headwall flashing is supposed to come on top of the shingle; otherwise, it doesn’t do anything there. It just drives water right in—it helps bring water into the house.

We took the top two layers of shingles out right before this wall begins—this dormer. And of course, water comes down here. It was all getting trapped in. You can see the nail heads are rusted to beat the band. These rusted off completely—and these.

EDITOR'S NOTE: Water generally runs downhill. Layers in a building assembly should be overlapped with upper layers overlapping lower layers to direct water out of the assembly. Otherwise, you are building a water injection system.