Upstate New York, near Albany. We had this roof put on about a year and a half ago, and it didn't leak until about 2 weeks ago when during rain about 4-5 gallons came through near center of long slope back section (see photos). The water came in at several points along the slope and at the wall at the bottom of the slope. Yesterday it rained again and water came in again in the same places. The back section faces west which is where prevailing wind comes from. I suspect that water is getting in along the seam between the small peaked roof and the long slope back section. You can't see it very well in the photos, but there's a black foam material along the bottom edge and along that seam between peaked roof and back section. The foam may not be as snug as it was on installation; I'm also not thrilled about the gaps in the trim at the seam.

Suggestions for fixing this would be greatly appreciated!

 

Screw pattern is off and there's not enough overhang on that lower roof.

 

Could you tell me what you mean about the screw pattern being off?

When you say there's not enough overhang on lower roof, I think you mean that the peaked roof should extend longer or further over the lower roof? If so, would the metal roofing from the upper roof just be longer, or would there be some kind of bracing for the overhang part? I'm wondering, if the overhang isn't braced or supported underneath, then couldn't strong winds get under it and either force it up, or blow driving rain up past the upper edge of the lower roof?

If a continuous piece of flashing is bent into a "Z" shape and inserted at the seam under the upper roofing and over the lower roofing, would that keep water from getting blown up over the top edge of the lower roofing? Please see scan of sketch: the red would be the piece of flashing insert.

Thanks!

 

You really need a flashing like your drawing the only problem is the roof isn't flat which means there will be gaps under the flashing. Extending the the flashing that's there would probably help.

 

With any transition like that, you must have an "under-over" flashing as you described. I can't believe any installer would omit this from the roof. If it extends down onto the lower roof about 12", I don't think you will have problems with capillary movement. Plus there is a gap on the rake that should have been solid.