My name is***** am a different expert on the forum. Your prior expert had to step away (this sometimes happens).
I have reviewed your post and if I understand correctly, your matter deals with construction defects (you purchased a home with a porch extension. The construction occurred at least 11 years ago (if not more). The porch is now showing signs of significant damage due to improper construction techniques).
Unfortunately, you are likely without any remedy in this circumstance. Florida has a statute of repose for construction defects of 10 years (see: http://www.floridaconstructionupdate.com/2014/01/26/statute-of-limitations-and-statute-of-repose-in-florida-construction-law-matters/). This means that even if a defect is "latent" (invisible to the naked eye, and there are no outward signs of problems), the homeowner/property owner must bring suit within 10 years of completion (the article I referenced gives more details on this). This type of statute of repose is common throughout the US and is one of the more generous ones.
Similarly, most homeowners and HOA insurance policies do not cover construction defects. While it is possible that a carrier could write such a policy, the premiums for such a plan would likely far outweigh any benefit. Unless you have negotiated an unusual homeowners policy, or your HOA has negotiated an unusual policy for the common areas, these policies will not cover construction defect.
As far as the HOA covering your porch area vs it being a separate interest, I would speculate (keep in mind, this is an internet forum, I am not able to review your CC&Rs/governing documents and cannot provide you with a formal legal opinion), that this patio area is part of the "separate interest" (meaning it is your responsibility not the HOAs). I am basing this speculation on the fact that only a few of the units have these extensions, the area is separated for your use alone (you have it screened in so that only you can use it), the HOA's attorney is taking the position that they are separate (I am not telling you to blindly accept their position, but I want to let you know I am taking this into account with my speculation). To come to a more thorough understanding of your rights vis a vis the HOA, and maintenance responsibilities for the porch (keep in mind, if the HOA is responsible for maintenance and they deem that not all condos are entitled to porches, they may simply remove the porch!), review your CC&Rs carefully, look specifically to their definition of what is "common area" and what is "separate interest" - this is where the distinction will break down.