I am adding an addition to my house in Los Angeles. The slope of the roof on the addition is 1/2:12 and the existing roof is 4:12. I would like to use single-ply TPO membrane on the addition due to the low-slope and energy efficiency. It is at the back of the house, so not really visible from the street so appearance is not an issue. My question is how to properly transition from the membrane to the shingles. I am afraid of wind driving rain under the shingles at the peak. We are still at the planning stage so still time to change the design of the structure if needed.
Thank you for any advise you may have.