How much can a lot be covered by buildings?

My neighbor owns a 16’8″ wide x 100 foot lot that’s currently built with a 38 x 16.8 3 story plus cellar. They’ve started excavating almost all the backyard to prepare space for a foundation for a two story extension. From the DoB I’ve ascertained that from the square footage they’re adding in the extension means it’s going to be 30 foot long. That will mean that 68 out of 100 feet depth will be built on. It’s zoned R6 but in the partial approval they’ve received from the DoB they’re changing the CofO from a 3 fam to a 3 family plus Office.

I thought there was some limit (like 50%) on how much of the ground R6 lot could be covered by a building.

Am I wrong?

By AussieCobbleHill |