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 Designing for movement rather than against it is an old admission in building practice. It came from watching real structures in the weather and noticing that the face of a building the sun is on runs warmer than the face in shade, so the two sides of one frame want to be different lengths at the same moment. This is for developers, facade consultants and structural engineers deciding how much tolerance a tall building needs and where to spend it. On a low building the difference is small enough to absorb without much thought, and the convention that grew up around it looks like housekeeping. On a tower the same effect accumulates over height, and the housekeeping becomes the design. Why does a tall building move when the sun hits one side? Because the sunlit face gets warmer than the shaded face, and warm material is longer than cool material. One side of the frame grows while the other does not, so the tower curves gently toward the cooler...

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 On every building I have worked on that had few precedents, there has been at least one assembly sitting in a laboratory with nothing behind it in any code table. The thing is real. It is fabricated, instrumented, waiting for a load, and it has no permission to be installed in the building it was made for. That gap, between a product that exists and a product a city will accept, is the subject here. I am writing it for developers about to commit to something unusual, for architects of record who will carry the filing, and for construction managers holding a schedule around it. The route through the gap is well worn, and almost nobody plans for it the first time. A code carries what has already been proven, written down as classifications, standards and acceptance criteria. A product outside that record is not forbidden, only unrecognized. Unrecognized is a condition with a procedure attached to it. What happens when the building code has no ...

By Michael Stern, JDS Development Group The question an architect asks me first about the base of a tower is why so much of it goes to cars. On a site where the rules require parking, the number of spaces is fixed before the plan is drawn, and a number of spaces is a volume of building with a geometry of its own. This is written for the developers, architects and planners who have to decide what the bottom of a building must be before they can decide what it might be. A parking space stops being a number the moment it reaches a drawing. It becomes a stall of a given size, reached by an aisle of a given width, served by a ramp at a slope a car can climb, under a structure with the headroom a vehicle needs and a floor to floor height no apartment would ever ask for. Where the rules require parking, the requirement attaches to the residences on the zoning lot and is written as a count. That count is the first fixed quantity on many sites. Floor area can be moved, massing can be argued...

By Michael Stern, JDS Development Group 111 West 57th Street and The Brooklyn Tower both have to answer the same question, and the question has nothing to do with how either one looks. It is what the building actually does in wind once it is finished, occupied and standing in weather that no model produced. This is written for structural engineers, for wind consultants, and for the developers who end up paying for the instruments that answer it. The first is the tallest and most slender residential building in the Western Hemisphere, built in the courtyard of the landmarked Steinway Hall and designed by SHoP Architects. The second is Brooklyn's first supertall, rising out of the landmark Dime Savings Bank. One is a needle threaded into a constrained site and the other grows up out of a masonry banking hall, and those two starting conditions hand the wind two very different objects to push on. Measuring a scale model in a wind tunnel has been the accepted basis for tall building...

By Michael Stern, JDS Development Group A steel column standing inside an old building usually carries nothing on it that says what it is made of. The mill that rolled it worked to its own practice, the drawings that specified it have often not survived, and the strength of the metal is a question rather than a recorded fact. This is written for the developers, structural engineers and preservation consultants who have to decide what that column may be asked to carry before a conversion is drawn. Why Old Structural Material Has No Reliable Paper Record Structural steel and structural masonry were in heavy use before the trades that made them agreed on common grades and common ways of describing them. A mill sold what its own furnaces produced, a brick came from whichever yard was close enough to cart from, and the building that resulted was a record of local supply in a particular year. Two columns on two floors of the same frame can be different metal. Masonry is worse in this re...