Skyscraper Museum Showcases New Construction Techniques that Reduce Environmental Impact

In the 1880s, New York had hit a brick wall, literally and figuratively. The problem was that buildings had gone about as high as they could go, based on the centuries-old technology of piling bricks on top of each other so that the structure was supported only by its exterior walls. New York’s tallest surviving example of this approach is a matter of some dispute, but a credible candidate is Lower Manhattan’s Corbin Building (right), at Broadway and John Street, which is eight stories (135 feet) tall.

The dilemma that limited the height of the Corbin Buildings was solved by the development of reinforced concrete: steel bars encased within a slurry of cement, water, sand, and rock, which hardens into stone and forms a building’s “skeleton,” allowing office and apartment towers to soar many dozens of stories (and hundreds of feet) skyward. This innovation—borne of the marriage of two strengths: steel is strong when you pull on it, while concrete is mighty when pushed down upon—made possible the skylines that define our urban world.

But what if a new material could replace structural steel, making skyscrapers lighter, cheaper, faster to build, and more eco-friendly? And what if that new material were actually much older than steel? This is the subject of a new exhibit at the Skyscraper Museum, “Tall Timber: The Future of Cities in Wood,” which spotlights the latest wave of reinvention among architects and engineers, focused on “mass timber.” Also known as cross-laminated timber (CLT), this is essentially plywood in which each layer (or “ply”) is solid hardwood an inch or more thick, rather than the cardboard width of the strata in ordinary plywood. The result is a building material that compares favorably to steel-reinforced concrete when strength is measured against weight, can often be less expensive, and has a much lower carbon footprint than the production of either steel or concrete.

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