This is in Brooklyn, but could just as easily be anywhere in Queens. Courtesy of IMBY:
Here's my guess... Someone picked this house up at an estate sale under market with the big get rich quick idea of maxing out the FAR and flipping it... Pretty big mess for just an additional 515 sq. ft. of living space, no?
Why would this block be zoned R5B if not to encourage this type of eyesore?