How do I join a metal roof to siding?
How to make such a junction – a visor of metal roofing to siding?
Make it like the end part of a skylight. Flip the bottom part like a "tie," fold one edge under the shingles, and attach the other to the siding trim. Bring the edge to the end of the shingles with a slight bulge. The inside corner can be flipped over the top at a 90-degree angle to match the color of the shingles or siding.
I do this way: after installing the roof, put the wall, and in the usual version (without siding). You need to make a cutout in the wall, where the edge of the wall is inserted and caulked or plastered. In your option, you just put a J-profile, and mount the siding.
What prevents rainwater from getting under the siding? For example, a metal tile roof or profiled roof. That's at the very bottom where the end of the canopy and the J-profile. What will you cover that corner with?
It goes eaves slat, put one slat directly under the roofing material, and the other descends into the gutter. This is a vulnerable point, I agree. But if you fit the eave bar exactly (you can run it not much under the siding and seal it), it will have a good effect. Try to press the panel against the J-profile as tightly as possible.