
Porch build - Looking for advice on metal roof to shingle tie in
I'm planning to build a lean-to porch roof attached to my house and would appreciate some guidance before I start. I've done plenty of framing and finish carpentry, but this will be my first roof tie-in, and I want to make sure I get the waterproofing details right.
The plan is to:
- Remove the existing eaves over the porch.
- Cut the rafter tails back and install a ledger.
- Frame a new porch roof at about a 1/2:12 slope.
- Install a mechanically seamed standing seam metal roof (not exposed fastener).
- Tie it into the existing asphalt shingle roof.
The framing part makes sense to me, but I'm less confident about the flashing and waterproofing details.
A few questions:
- What specific flashing pieces should I be using where the new standing seam roof meets the existing shingle roof?
- Headwall flashing?
- Transition flashing?
- Z-closures?
- Butyl tape?
- Anything else that's considered standard practice?
- Are there manufacturers or suppliers you recommend for the metal roofing and flashing?
- If you were doing this yourself, what are the common mistakes you'd avoid?
- Any tips on sequencing? For example, when to install the membrane versus flashing, and how you lap everything so water always sheds correctly.
Here is a video that I found to be the most helpful and we generally plan on following suit (except with a metal roof): https://www.youtube.com/watch?v=cr4WozliZMM
If anyone has photos, videos, diagrams, or manufacturer details they've followed successfully, I'd really appreciate seeing them.
Thank you in advance!