HOA will the exterior and common areas of the building.

Exterior walls standing, new roof, interior walls, siding, no landscape, no patio, with 2 car garage, you're looking around 200-250/sf if you want high end. i like those size projects.

I called the local Sherwin-Williams and they have a product for reduced permeability called Resilience but it appears to only be for exterior use. 

I am a project manager for exterior construction so I don't deal with interior jobs, but you should be able to know at least 80-90% of what needs to be done and what the real cost is through estimating the project.

Often times for my buy and holds I'd love a few months to get income flowing before I start spending to fix up the exterior of the houseSpeaking of which, anyone want to help me paint the exterior of a duplex?!

While condos can be a pain in some ways, the condo association owns the exterior walls which is where any damage is likely to be.

If your roofer can tell that the pitched portion of the roof has 8 layers on it, I would think he should have been able to do the same for the flat portion using the same methods, unless this area had no exterior edges because of where it was positioned on the roof.

Grey is the new beige.Greys with white trim (interior and exterior) is what sells around here.  

This conversion would allow the now 1 bedroom unit (converted from studio) to have private access from the exterior.

Some may be ok with properties like this as the comparison would be that the fees cover roof, common grounds, exterior insurance but regardless, I look at it as eating away any kind of return.As others stated, you would do well to get the documents and P&L if you can to see just where the money is being spent and what they cover.Good Luck!