@Mike Wood @Jaron Walling @David Butler.  

This is why you see most homes in the area surrounded by high walls to protect against flooding.

Along the way discovered some of the walls were rotted out due to previous termite damage.

I have seen walls that you would assume that are on the property line be more than 2' on one side or the other.  

Quote from @Jaron Walling: That's an 81sqft bedroom.

At another point, the wind blew down a brick wall he had just "secured" onto the epdm mule hide layer he had just laid down.

It's all about bolting and anchoring into the wall.

What I can assume is most AZ HOA's don't allow building new structures above the height of the exterior block walls.

All depends on the relationship, though I did hire a cigar / drinking buddy to do some contract work but this was only after I helped him sheetrock some walls and learned what he was capable of.

Recently, I discovered that I'll likely have to repair the foundation of my house to prevent any new cracks from forming through the cinderblock walls, however, I'm not sure other large expenses I should look out for.