Why Is the Floor of the Oculus Already Crumbling?

Photo: Christophe Bonanos

Look up as you walk through the Oculus at the World Trade Center and you can forgive almost anything. Yes, the cost exceeded $4 billion for little more than a pretty front door when the rest of the transit system starved. Yes the central skylight was supposed to open every 9/11 but it didn’t because the seal tore the second time they tried it. (The solutionfor some time was flexible ribbon.) Yes, the mall is underperforming, and in the middle of the lobby there are too many small, squat booths selling souvenirs. But you walk into this room, and she does what Santiago Calatrava said she would do. Your eye is drawn to the Italian marble walls and crisp white ribbing, and reminds you of the nave of a grand cathedral. You may experience, as a commuter, a moment of uplift.

Take a look down, however, and you’re back in a splintered New York.

The white stone slabs that make up the lobby floor are chipped and chipped around the edges. The corners are broken and thousands of scuffed soles have ground dirt in the rough spots, blackening them and making them very visible on the honed surface. You can also see where a scatter of tiles has been replaced, as the new tiles are whiter and shinier than the others. The building opened just seven years ago, in March 2016, and the rest still looks fresh and new. The ground no. Grand Central Terminal will be 110 years old in a week, and its Tennessee marble floor shows slight waves of billion-foot wear, but relatively few cracks and chips. It is probably in better condition.

I’ve asked Port Authorities in New York and New Jersey about replacement work, some of which I’ve seen underway in the last year. Its representatives issued a statement, “As part of the agency’s ongoing facility maintenance program, normal wear and tear on Oculus flooring is addressed by routinely repairing and/or replacing damaged tiles,” adding that he had stopped for the holidays and “will resume later this year. I also asked Calatrava’s office, and his reps declined to comment. Neither would talk in detail about the beaten ground .

The simplest guess, but not necessarily the correct one, is to blame the stone. This is called Lasa marble, extracted in Italy and brought by a Vermont importer. It has few visible veins, it is fine-grained and extremely uniform in color, pure and slightly translucent. On the Mohs scale, which you might remember from Earth Science class, it’s about a 3 or a 4: soft but not too soft. (The granite is about a 6 or a 7.) The slabs are one and three inches thick. Monuments all over Europe are made of Lasa marble, as are approximately 90,000 American soldiers. tombstones.

Raffie Samach, an architect who worked with Calatrava at the start of the project (and remains an admirer, calling the architect and the building “amazing”), said: “I was surprised by the choice of materials. It’s not what I would use in a public space – although we all have to admit it looks beautiful. However, he was quick to add: “I can also say that whatever materials were offered, they were vetted by the Port Authority – and they were very particular about sustainability. Civic agencies, I suggested, tend to be conservative about such choices. “Obsessively.”

I decided to do a little comparative test, so I got my hands on a sample of the floor of the Oculus and another of that of Grand Central. (It doesn’t matter how.) They’re about the same thickness, and the grain texture looks similar. When I rubbed the rough sides together, the difference became obvious. The beige stone of Grand Central remained intact. Lasa’s white marble spilled crystalline crumbs that looked like sugar all over my desk. It is clearly more fragile.

It tells you something but not everything. Don’t forget that, despite appearances, it’s still stone, not a piece of dough. The smooth top surface of my sample doesn’t chip when you hit anything against it. Certainly, he should be able to deal with Louboutins and wheeled bags, right?

Part of the problem is just that we can see every little bit. The New York Public Library is also marble, albeit from Vermont, and it’s a little melting around the edges after a century of urban wear and acid rain. It looks nice all the same, mainly because it’s a Beaux-Arts building, full of filigree and detail. Weather is part of its appeal. Calatrava’s designs, being geometrically pure, even show small dents not like patina but like damage, and your eye goes straight to each one.

But that’s not all that’s going on here. Matthew Crawford, manager of a company called Gem Construction and Waterproofing, oversaw much of the installation and upkeep of the floor, and when I called him, he immediately understood what I was asking for. He mostly dismissed my suggestion that the choice of stone was the fundamental problem, although he agreed that it was “not the strongest. There’s millions of little hammers, every day, pounding this ground. I would see a woman in stilettos running there and I would cringe. The deeper problem, he explained, is that there is a radiant heating system below the type you see in lots of premium build these days. Thin pipes meander, back and forth, over a layer of insulation, and they are filled with a glycol solution which is heated and pumped. Radiant heat has many advantages – uniformity, quietness, no vents to collect dirt or blow dust away – and a warm stone floor is pleasant in the cold months. As it heats up, stone (like all materials, although less so than some) expands. The edges press against each other, harder and harder, and eventually break.

Engineers usually accommodate this movement with an expansion joint – a small gap that can stretch and shrink as needed – and there is indeed some on the floor here. “We recommended an eighth of an inch between joints with caulk,” says Crawford. The Calatrava-Port Authority team rejected that idea, he says; adding wider gaps would have altered the alignment of the stones, after which “the seams would no longer line up with the joints of the walls”, as the architects had specified. Instead, he said, engineers stuck to their plan for relatively few, widely spaced relief joints. “There’s one every stone ten by ten, roughly.” I scoured the ground a few days ago, looking for them, and that approximation seems correct. They’re only a hair’s breadth wider than cemented joints, and if you kneel down and press your fingernail against one of them, the filling is rubbery.

But, I suggest to Crawford, couldn’t they have cut a shard from all the edges of each stone slab and thus preserved the alignment? “Yes, but it would have cost more.” Could the stone have been set more firmly, so it moved less? “Yes – with a thicker laying bed” the mortar underneath would have limited its movement, “but that wouldn’t give them the R-value they wanted” – i.e. less heat would pass through the floor, compromising the building’s LEED goals. As an aside, he also mentioned that there had been glycol leaks in the heating system and you could see brown stains on the floor here and there. “I don’t want to get anyone in trouble,” Crawford said regretfully, “but we told them.”

There is, in the Oculus, a proof of concept. The floors on the upper levels are made of the same material but lack the heating system below, and they are in much better condition. (Admittedly, they’re a little less heavily trodden, which may also explain some of the difference.) More than that, however, Crawford’s company also got permission to refit a section of floorboards, one that was missing pipes. heating, with a thick bed of mortar, as he had recommended. It sits in front of a freight elevator on the northeast corner, where seasonal exhibits and heavy equipment are brought into the building. It’s probably the busiest area of ​​the place, he says, and “I walk by and check every time I’m there.” The other day I did the same. It remains almost intact.

The Port Authority seems to have followed some of this advice late. I did the same nail test around a few of the newly laid replacement stones, and most of them appear to have been caulked rather than cemented. This is an expensive set of repairs, however, and until the entire floor is resharpened – a multi-step process similar to sanding a hardwood floor – it will look a bit uneven and unequal. Resharpening a scope of this size will likely cost upwards of a million dollars per shot, and if the AP has to do it every year or two while the damaged stone continues to be replaced, that starts generating real money.

Has authority indeed brushed aside some real-world concerns in the service of Calatrava’s aesthetic? Neither the Palestinian Authority nor Calatrava’s firm speaks. But Samach, during our conversation, reminded me of the mood surrounding this site in the early years after 9/11. New York (not to mention the nation as a whole) was in agony, feeling hurt and desperate to regain a sense of its power. The instinct when planning the Oculus was that almost no expense was too much, no detail was too much trouble. We were going to have something Perfect there, the best in the world. And while that intensity of feeling was met with a lot of practical concerns, cost overruns, political fights, and a growing realization that maybe this project wasn’t going to do everything we clung to , the central spirit persisted: it was going to be beautiful , and maybe this time we could leave the practical aspect aside. But to accept that today, you have to look away. Just… look up.

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