From Lost City:
I am guessing that, with the new Carroll Gardens downsizing rezoning is on its way to being a reality, atrocities like this two-story growth above a brownstone would no longer be allowed. Let's hope not.
I sent this to someone who would know. The response:
"Actually - this development would still be allowed under the new zoning. Carroll Gardens was rezoned R6B and should have been rezoned R5B. R5B has max height of 33'; R6B has a 40' streetwall and a 50' height limit."