Michael Stern

By Michael Stern, JDS Development Group Every site carries a limit on how much of its own ground a building may stand on, and that limit is settled in plan long before anyone draws a section. Two of our towers answer it in opposite directions, and what separates them is a decision about plan rather than about size. This is written for the developer, the architect and the zoning consultant standing over a constrained lot, deciding a footprint. The footprint is the decision that closes the most doors behind it. 111 West 57th Street is the tallest and most slender residential building in the Western Hemisphere, so it stands on very little ground and takes its area upward. The American Copper Buildings occupy a former Con Edison site as twin towers with open ground held between them. One question about the ground, two answers. What does lot coverage actually measure? Coverage is the portion of a zoning lot that a building would cover when the lot is viewed directly from above. It is ...

By Michael Stern, JDS Development Group The first document I read on a site with an old building on it is the one that designated that building, and it tells me more about what the project can become than the survey does. Two buildings can stand on the same street, built in the same decade, and answer to different rules, because one was designated on its own and the other is protected by the district drawn around it. This is written for developers, architects and preservation professionals working out what a conversion may ask for before anyone draws it. What the designating document actually says The report that creates a landmark is a reasoned document rather than a label. It names what is being protected, states why it is being protected, and then describes the features that carry those reasons. Everything a reviewer does afterward refers back to that description. For an individual landmark the subject is one building, so the reasons are specific to it and the significant featu...

By Michael Stern, JDS Development Group Photo by Julien Riedel on Unsplash A lot I looked at recently carried a base district designation that anyone could read off the public zoning map in a few seconds. The rules that actually governed what could be built there took a zoning consultant the better part of a month to assemble. The designation was accurate, and it was also the smallest part of the answer. A special district had been drawn over that block, a contextual rule governed the street wall along one frontage, and the lot carried a designation that no district color on any map records. This piece is for developers, architects and land use professionals who have to decide whether a site is worth a full analysis before anyone has paid for one. What the base district on the map actually decides The base district is the layer everyone starts from because it is the layer the map is drawn to show. It sets the broad quantities: how much floor area the lot may hold, what uses are p...

By Michael Stern, JDS Development Group Photo by Wojciech Wyszkowski on Unsplash A zoning district boundary does not stop at a property line. It is drawn on a map at the scale of a neighborhood, and now and then it runs straight through the middle of a single lot, leaving one piece of ground answering to two sets of rules at once. If you develop on constrained urban sites, or you advise the people who do, the split lot is the condition that most often explains why a building on an ordinary looking site came out in an unusual shape. What follows is how that works, in order, because the order is the whole insight. The floor area on such a lot is not computed once. It is computed for each portion, under the rules of the district that portion sits in, and the building is the sum of what those two computations permit. How Floor Area Is Computed on a Split Zoning Lot Start from the ground. The lot is one parcel in the deed and two parcels in the zoning, and the line between them i...

By Michael Stern, JDS Development Group A foundation is completed on a Thursday and the zoning that governs the site changes the following week. The building that foundation was designed for is still legal. The building the new text describes is a different one, and nobody is building it on this lot. This is for developers, land use lawyers and construction managers working on sites where the rules move while the schedule runs. The mechanism that decides the outcome is a recognition, written into zoning itself, of work that has already substantially begun. What it protects is progress in the ground, and what it turns on is a very small number of dates. What Zoning Protects When Construction Has Already Begun A zoning amendment does not reach backward through every project on every lot. Text and maps change constantly, which is ordinary work in the planning profession and a standing condition for anyone developing on a long timeline. A project that has reached a defined stage of ...

By Michael Stern, JDS Development Group Photo by Parsoa Khorsand on Unsplash An owner of a five story building on a good block asks what it would take to add three floors, and the answer comes back from the title report rather than from the zoning map. The lot still has a district, a permitted floor area, and a shape. What it no longer has is the unused area that once sat above the roof, because that area was sent to a neighboring lot years ago and it is not coming back. This is written for developers looking at assemblage, for land use lawyers who field the same question from the other direction, and for owners of small buildings who assume the room above them is still an asset they hold. The mechanism is ordinary. The consequence is permanent, and that combination is rare enough in this business to be worth understanding before anyone signs anything. How Floor Area Leaves a Lot Permanently Unused floor area is an arithmetic difference. It is what the zoning permits on a lot les...