I believe it's from an update to IRC codes back around 2015. 

Only about 25% of the Parks I've prospected in are strictly owner occupant.

Some brokerages are quite strict on what deals are allowable and many of the big names don't allow wholesaling at all.

Every day I see posts and pleads on social media for people desperately needing a place to place their home without fear of being "red tagged".I'm working to Bring Tiny, Home.I really suggest you take a deep dive into the City Of Portland Oregons new development code for these units.. it will lead the nation.. and something you can share with regulators in your jurisdiction. 

He had been getting notices regarding the property violating code until the city stepped in and put him on notice.

For example, most areas in Pinellas county have very strict regulations when it comes to this kind of investing. 

Also I tried to find the IRS code 1031 section original text but couldn't.

Is it suitable for an owner occupants or strictly an investor play?

A partner and I own a warehouse in a small market that we're interested in converting to self storage, but it's in a "mixed commercial/residential" zoning part of town, and the only zoning classifications that are permitted to build self storage per their code are the purely commercial zones.

IT is costing me about $24,000 to do this because I have to bring the electrical system in both apartments up to current code, plus buy new HVAC units and all new ductwork separating the units and water heaters.