FHA Handbook 4000.1 covers this quite extensively, including how to configure properties with these features in the SCA. Not trying to be snarky, but I would suggest reviewing the relevant sections of the handbook.
I have, and the next time I do an appraisal for a HUD transaction, I will again. In the meantime, here is the applicable portion of the HUD 4000.1, p. 441:
"iii. Additions and Converted Space
The Appraiser must treat room additions and garage conversions as part of the GLA of
the dwelling, provided that the addition or conversion space:
• is accessible from the interior of the main dwelling in a functional manner;
• has a permanent and sufficient heat source; and
• was built in keeping with the design, appeal, and quality of construction of the
main dwelling.
Room additions and garage conversions that do not meet the criteria listed above are to
be addressed as a separate line item in the sales grid, not in the GLA. The Appraiser must
address the impact of inferior quality garage conversions and room additions on
marketability as well as Contributory Value, if any."
I don't know if this rises to the "quite extensively" standard, but is certainly adequate guidance for most of the additions/patio rooms/enclosed decks I've encountered.