I have a background in construction project management, understand building codes, can operate heavy equipment, and can perform most single-family residential construction work myself.

Your phrase "doesn't make sense" basically applies to the entire tax code.

Sure we use pretty big data sets and demographics to take out big chunks of markets that don't qualify, or refine big areas, but working with things like "desirable zip codes" is simply too large of an area to be focused on accurately, at least in my midwest market. 

I ran into this issue when I initially started learning about long distance investing and I created www.zipfinder.co which aggregates a wide range of data on a zip code level to help streamline the research process for investors. 

Was it permit issues (work done without permits), code violations, or something structural?

For RE Investors there is a cap on deductions but not for RE professionals (per the IRS Code).

Feel free to contact me for my friends and family discount code. 2.

Tax code changes or compliance burdens?

The uglier the property, the less competition for it and hence, the lower the price.We've got an interactive map on our website that has color-coded the Classes of the 132 Metro Detroit Cities and 183 Detroit Neighborhoods to help investors understand where to invest.DM me if interested in chatting further...

NYC is tough, but still doable if you stay owner-occupied and focus on neighborhoods where the numbers work, not just the zip code.