The re-roof will include two types of construction. One is replacement of an existing shingle roof. The existing roof deck is planks, not plywood. I plan to spray-foam insulate the underside of the deck and seal the attic.

The other two roofs are flat-roofed additions. There, I plan to frame with minimal rise for the metal roofing. These areas will be sloped in different directions (right angles). One is a lower-slope continuation from one of the gabled roofs. The other will border on that and end at the gable end. The existing roofing has to be removed to eliminate the vapor barrier and that will also be spray-foam insulated before the metal panels go on.

I'd appreciate any advice that is offered. I have some specific questions. Are there different options for treating the edges of the roof? What are the choices for underlayment? This roof will be difficult to get onto safely compared to shingles and the flat roof. Is there any practical way to install attachment points for a safety harness? (I am planning on installing both photovoltaic and solar thermal. I have nearly South-facing gable on both the house and garage.)

I understand that the metal is lighter than the shingles that will be removed. The dead load will be less. Do I have to be concerned about the corresponding increase in the live load? This is Gulf of Mexico hurricane zone (New Orleans). I wonder if hurricane ties should be added at this point if it is practical.

Thanks for reading!

what do you currently have on flat roof
additions?

If anyone can advise on the details of metal roofing, I will be very grateful.

If anyone can advise on the details of metal roofing, I will be very grateful.

If anyone can advise on the details of metal roofing, I will be very grateful.

I had a metal roof installed last year and yes, there were options for the edges. My underlayment was a titanium synthetic and varying grades were available.
Every contractor is different- answers you receive here may not always be the same answers you would get from a local guy looking at your house.

Call guys, get estimates, ask questions!
It is free.
This part of the process can be very educational if you approach it as such. Every topic you discuss in person with an expert who is literally looking at your roof leads to more topics and more understanding of the process. Between contractors interviews and further more specific research as you get deeper into the process, by the time you sign your contract you should have a very clear understanding of the hows and whys as they pertain to your individual situation.