Most likely, you're home isn't zoned for a roof deck, which means that you'd have to go for a variance of local zoning laws from the town to gain permission. This would be on top of preparing architectural renderings of the deck and having a structural engineer certify that the building can withstand the weight of the deck.
It's not an easy task, but it can be done.
Your first step is to call the zoning board at (201) 420-2068.
Prudential Castle Point Realty
203 Washington Street
Hoboken, NJ 07030