Living in a fairly urban area where stations are located in all directions from where I live. In my main system I have a Yamaha CT-7000 that works very well with an external Omni-directional whip antenna that is about 20' from the house and about 25' elevated. It already had excellent reception and does not seem to be effected by the new roof. The T-2 with the internal di-pole is now very comparable in reception to the CT-7000 setup.
No, not required per code here.
That is what I was thinking. My office is on the second floor over looking an attached garage. Both the roof above the office and the roof above the garage are now metal. The di-pole is mounted on the external wall beside and above the garage which places it between both roofs but not necessarily masked by either one. I think it may be a combination of reflector and/or ground plane that is helping the signal? It any case, it works quite well. I'm now picking up a weak signal from a college in Bellevue that I really enjoy. I could barely even pick up the signal before on the T-2.