The de Blasio administration’s newly announced Housing New York plan has set many ambitious goals for the development of new housing in the city – and has acknowledged that extra floor area for residential construction will be necessary.

CHPC’s board members are on the front lines of developing affordable housing. As such, they provide valuable insights into how the city can construct more housing, and improve its design and quality.

Recently, some of our board members had begun to raise an issue they had been experiencing that was constraining residential development. The rules that define the building envelope within contextual zoning were making it difficult, sometimes impossible, to fit the allotted floor area into their building. The building envelope defines the maximum three-dimensional shape that a new building can occupy.

We decided to take a closer look at how the building envelope rules within contextual zoning can sometimes result in fewer residential units being built.  We examined seventeen sites to see how much the building envelope rules affected the residential construction.

Our study found that eight out of the seventeen buildings were unable to use all of their allotted floor area because of the building envelope rules. In other words, it is often the building envelope that is the determinant of the development capacity of a new building rather than its floor area.

Our work has helped to begin a dialogue with the de Blasio administration to see how these rules, put in place decades ago, could best be changed to reflect the realities of constructing residential buildings in New York City today. We look forward to supporting their efforts at reforming these technical barriers as the Housing New York plan gets implemented.

You can view the report below:


You can read the full report on the Building Envelope Conundrum here.