Zoning question for SFH vs Duplex

[Ben Robertson]

I bought an empty a while back for a good price and I want to build on it. It's currently zoned A-5 which is a single family detached home with a lot size of a minimum of 5,000 sq. ft. The numbers for a duplex look better than a SFH but I'm wondering if I would have to get it re-zoned to a 'B' which is for two family homes.

Has anyone ever re-zoned anything in Ft. Worth? Would re-zoning this be a mere formality or would it be a big pain? 

Thanks for the help everyone.