Glenn,
I would say that it is raintite and may fit the description of a Sunroom, especially as it will also contain skylights. It is still undeniably an 'attached' structure in that it can be removed (most installations) at any time without compromising any part of the main house at all.
I started another Discussion on the wiring requirements at:
https://www.electrical-contractor.net/ubb/Forum2/HTML/000347.html Bill
