Failing an agreement with the neighbor your recourse is to go to your repective city and ask if they can help. Some cities have clear laws in place that handle these issues and other do not.
If either of those two options do not give you the results that your looking for then you will have to seek legal help, however, your most important homework has been completed for your counsil to act on. Good luck to you.
Jeff Daley, PhD
Licensed REALTOR® State of Arizona
Ryan Buckley Realtor®
Turning your Dream into an Address
Coldwell Banker Residential Brokerage
As I understand it, the fence was built inside his property line. You want to claim those 3 feet.
You have to do something first, if you haven’t already done it. Then, there is a easy way and a hard way to attempt to do this - you won’t control which option is available, and legal representation will be a must. The first step, and whichever second step is available, will all involve a significant expenditure of your time and money (the hard way can be very expensive). So there is no quick and easy way.
This situation causes an ongoing legal issue. When you decide to sell your home, it will require that you do certain things. I can tell you what those legal ramifications are at that time.