Michael Stern

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 Put two of our buildings beside each other on a single variable, which is how much of the new work a person standing on the sidewalk can actually see. The Brooklyn Tower rises from the landmark Dime Savings Bank, and everything added there is visible from several neighborhoods away. Walker Tower is a Ralph Walker Art Deco telephone building conversion that added roughly 50,000 square feet, and almost none of that area announces itself to someone on the street below. That difference is not a matter of taste. On a designated building, new work above the existing roof is reviewed for what can be seen from the public way, so the shape of a rooftop addition is generated by lines of sight rather than by the floor plate that wants the area. This is for developers looking at a designated building with unused area above it, and for the architects and preservation consultants who will have to draw the thing. What a Rooftop Addition Is Measured Agai...

By Michael Stern, JDS Development Group Photo by Bekky Bekks on Unsplash On most assembled sites in New York City there is a masonry wall standing directly on a lot line, shared by two buildings that were never designed together. It is the oldest structure on the property and it is usually the only one still standing when the new building opens. This is for the developers, architects and structural engineers who are looking at a site like that and working out how much of it they actually control. A party wall is inherited structure. Everything the new building does along that edge gets arranged around masonry that was built for another purpose, by people who are gone, to a standard nobody wrote down. A Party Wall Straddles the Lot Line A party wall sits astride the boundary rather than beside it, with part of its thickness on each lot. Both buildings bear on it, which is what distinguishes it from a wall that merely stands close to the line. Two independent walls built tight agai...

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...

By Michael Stern, JDS Development Group Photo by Sebastian Hages on Unsplash Two lots on the same block each hold floor area they will never use, and a third lot sits between them. That third lot decides whether either of the first two can ever contribute to a tower, because under the general rule floor area moves only between lots that form a single zoning lot, and a zoning lot has to be contiguous. This is written for developers and land use professionals evaluating an assemblage, and for anyone who has looked at a block map and wondered why a small site can hold a tall building while a larger one nearby cannot. What a zoning lot is and why it is the unit that matters Floor area is counted on the zoning lot , a unit the zoning creates for its own purposes, which can be one tax lot or several tax lots treated as one under the rules. The deed map and the zoning map therefore disagree by design. The deed map shows who owns what, the zoning map shows what may be built where, and the...