Converting Garage to 4th unit on a Triplex

[Sheena Varghese]

Hello,

I bought a triplex few months ago.  The main house has two units and then there a detached garage with a unit above.  The garage is large and is currently divided into two sections.  I wanted to convert the garage area into a unit but the person I spoke to at zoning at the city said I couldn't.  I did not speak to an engineer at the city but the secretary who just looked up the zoning for that area and said it was for multifamily.  Is there anything I can do to possibly make this happen?  Is there such thing as appealing the zoning?   It is already a triplex, not sure why I can't convert it into a quadplex.  Thank you for any advice you can provide.