Even though we only make metal roofing and don’t do any installation work, we do deal with roof contractors and roofers every day. Having been in the business for more than three decades, you definitely learn a few things, including the fact that there is a very big range of skill-sets when it comes to roof mechanics.
Just recently we had a repeat customer (an architect) who had specified one of our custom profiles for a new home a couple of years ago, and then again this year. We supplied the exact same material for both jobs, but there were two different contractors installing the metal roofing. The first job was performed by a very experienced metal roof contractor who did the job quickly and cleanly, and the project actually won a design award. Unfortunately, the second contractor was reporting problems from the outset and had repeated issues with the execution of the job - even though there was nothing different on the material side!
There is nothing exotic in the installation techniques necessary to install a metal roof. Anyone who took Sheet Metal 101 in high school shop (if that’s still such a thing!) can understand and install any of our metal roofing systems with only a basic knowledge of roofing practices. Don’t let anyone tell you different. But the 80/20 (80 percent are ordinary to poor, and 20 percent excel at their trade) rule applies to roofers just like every other profession, regardless of their claims to be capable of installing “any kind of roof!”
By the way, the architect and builder changed installers to “save money.” Unfortunately, they they will have saved little or nothing by the time they fix the mistakes and get back on track with their custom home.