I've about got the metal on this tiny house and I'm having trouble figuring out how to install the corner trim at the top of the roof to make it look finished off. The roof is somewhere between a 3/12 and 4/12 pitch.

I'm just using standard corner trim.

enter image description here

What do I do about the part where the three trim pieces meet at the top?

I tried looking online but considering this is a slanted roof with no overhang in the front I couldn't find any examples to help me out.

If you have any illustrations or anything that would be much appreciated.

enter image description here

  • What is "standard corner trim" ? We can not see the pitch angle of the roof. more info will help.
    – Alaska Man
    Mar 23, 2020 at 22:30
  • Thanks, I updated it.
    – Mark
    Mar 23, 2020 at 22:44
  • It's hard to describe, but you should be able to cut a "V" shape into the top of your corner molding, where it would lay flat on the roof. Then snip a cut in bent part at the bottom, and bend it 90 degrees to form a corner piece that goes on last, after everything else. Mar 24, 2020 at 5:04

2 Answers 2


outside corner drip

Normally you'd have your wall siding overlapped by an overhang. I don't know what your roof details are but generally the detail would look similar to this foundation outside drip except the top of the drip flashing would then have a membrane on it. The corner wall flashing would be shy of the drip edge.

  • Yeah, I only put an overhang and drip edge on the lower side of the roof. I'm just going to run corner trim up the corners of the siding and on the edges of the roof (except the back) and put closure foam where I need it. It should be fine but I can't figure out how to cut the corner trim to fit together at the top two corners.
    – Mark
    Mar 23, 2020 at 23:14
  • How long are you hoping this will structure will avoid significant rot and leaks? It doesn't look like you live in the desert and the water management details on this structure seem shaky. I don't like buildings with no overhangs in general. Relying on closure foam sounds like it is designed to fail with the life of the foam or adhesive. Mar 24, 2020 at 5:05
  • 1
    For a decent amount of time at least. It's just a $3,000 tiny home/cabin, I'm doing it nearly all myself mostly by hand. I probably could have stood to do an overhang in the front and sides but I have windows in near the ceiling and I wanted them to have direct sunlight. The closure foam will only be downhill from the corner trims so maybe I have something to worry about with windblown rain but I feel like it will be fine. I get your concerns but it's just a pet project and I'm learning as I go.
    – Mark
    Mar 25, 2020 at 20:52

It fits to an overhanging roof. You'll have to come up with a custom detail

Here is a video, go to 12:20 Pro Level Metal Trim Details: Corner Trims


Adding picture for item referenced in comments

Roof drip edging

enter image description here

  • That's my problem though, I don't have any overhang on the tall side of the roof or down the sides. Maybe I gave a bad picture but I'm talking about the corner in the top right of the picture, where the three corner trims meet. I may have to just figure something out as I'm doing it but I wasn't sure if there's a method to it, or if I need some kind of corner box or extra piece to put over it.
    – Mark
    Mar 23, 2020 at 23:21
  • I think I understood, by corners you mean the corner of the building and the roof edges. The 'problem', I don't want to come across as mean, but it's that your roof doesn't have an overhang. That's not how it's done. You have do come up with something. I'll post a picture of standard drip edge which would go around the edge of your roof, but is used with soffit and overhang (at roof ends)
    – Ack
    Mar 23, 2020 at 23:26
  • I have seen plenty of metal buildings with no overhang but they're all gable roofs, so yeah maybe it's not proper the way I did it with it being a slanted roof. The corner trim I have should be fine but I'm just looking for a way to deal with this top corner where it won't leak or look completely jacked up.
    – Mark
    Mar 23, 2020 at 23:32
  • A slant roof is just 1/2 of a gable roof. Go look at them and see how they did it
    – Ack
    Mar 23, 2020 at 23:42

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