Counting down the top 15 pages of 2016. This one is #8. "This is the most important part to waterproof because this is the place where all the water will end up and it might leak if not done correctly."
All complex assemblies involving multiple trades demand the critical, and constant, focus of supervisors. Where one trade ends and another begins must show continuity. If you do not build redundancy into the system, you are building in risk.