The Symbol of

a New Age

The future of sustainable building: Wooden skyscrapers

Perhaps the most iconic building of the modern age – the Empire State Building – was chosen for our second Plan B case. Architect Michael Green from MGA contributed his visionary concept planning and his passionate belief that the future belongs to tall wooden buildings. Internationally recognised leader in timber engineering, Equilibrium Consulting, provided expertise on structural matters. Metsä Wood’s own material and construction experts rounded out the team.

As with each Plan B case our team’s challenge was to design a recognisable but modern version of the original using wood as the main material. The size and the basic structure are the same as in the original Empire State Building in New York.

While at first the idea of building such a tall structure out of anything but steel and concrete might appear whimsical – even foolhardy – Michael Green presents a growing body of research and actual projects that make a compelling case that constructing tall wooden buildings is not only feasible, but highly beneficial to our shared future.

Have a look at how architect Michael Green, Equilibrium Consulting and Metsä Wood's construction engineers made the new and improved wood architecture version of this iconic skyscraper.

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The team

The visionaries behind the wooden skyscraper

Metsä Wood shares a belief in the role of wood in the future of sustainable architecture with other leaders of the industry. For our Plan B Empire State Building project we teamed up with visionary Canadian architect Michael Green and his firm MGA. According to Green, “Wood is the only carbon-neutral material that we can build with that's grown by the power of the sun.” We also partnered with Equilibrium Consulting, an internationally recognized leader in timber engineering. They provide expertise to important industry suppliers throughout the world.

History

Wonder of the Modern World

Early skyscrapers first emerged in land-strapped areas of Chicago and New York City toward the end of the 19th century. Completed in 1931 in just 410 days, the Empire State Building rises 102 stories above Midtown Manhattan. For nearly 40 years it was the world’s tallest building – and a global symbol of the industrial era. Built of limestone and steel in the distinctive Art Deco style, it has been named as one of the Seven Wonders of the Modern World.

Inspiration

Aspiring to natural heights

In Vancouver where Michael Green Architecture is based, trees grow to 33 stories tall. In California, the redwood forest grows to 40 stories tall. Even in Nordic Finland, trees can grow as high as a 15 story building. A tree’s growth is only limited by its ability to push nutrients up its height, and not by the structural capacity of its fibres. Yet today’s wooden buildings rarely go higher than four stories – mostly due to building codes and outdated misconceptions. Green is a strong believer that high-rise wooden buildings are not only possible, but may be the most practical and environmentally sound solution to rapid global urbanisation and climate change.

Misconceptions about tall wood buildings are beginning to change. In the past few years the world has seen the construction of wooden buildings up to 100ft (30m) tall, setting records that will soon be broken by new projects under way that will reach as high as 250ft (75m).

And unlike other structural materials, wood products require no covering and can remain as the finish of the interior. Wood offers a beautiful interior environment that occupants gravitate towards and love to touch – every piece is unique.

Watch Michael Green’s Ted Talk on the wooden skyscraper revolution.

Modular design

An efficient ecological building system

The challenge was to go beyond all currently proposed projects and design a building out of wood five times taller than anyone has dared to imagine; to design an iconic building, representative of innovations in structural steel in the 1920’s, out of Kerto LVL engineered wood panels.

The overall building size, floor to floor height, and column spacing are the same as the original structure. The columns extend as much as 6 stories high, with moment connections at these locations to make each column structurally continuous up to 86 stories. Box beams connect the column along the short axis of the building. Four pretensioned cables run within these beams, tying the structure together from side to side. Kerto LVL slabs span the long axis of the building connecting the beams together and forming the top cord of the beams.

Kerto panels are made by gluing together wood veneers to make panels that are up to 8 feet wide, 82 feet (25 m) long, and of various thicknesses. These engineered materials are stronger than timber of similar dimension. We always know where the wood comes from and we only use sustainably grown, certified wood.

Transporting Metsä Wood's pre-fabricated building materials costs significantly less than other materials and methods. More building elements per truck mean lower costs, and also less construction traffic, dust and noise. And these same advantages also apply to the building process.

Choosing a system of prefabricated wood elements is less costly and more efficient. Our Kerto LVL modules are pre-fabricated in a specialised factory setting, resulting in the advantages of increased efficiency and quality control.

Our pre-fabricated sections are less costly to assemble once they arrive at the building site. Simple, precise connection points and lightness make for a faster onsite process.

Misconceptions

Safe, well-tested and rigorously understood

In the event of a fire, Kerto LVL performs more predictably than many non-combustible materials, and has a notional charring rate of 0,7 mm (0.027 inches) per minute. When burned, the surface of Kerto is charred, which protects the product, insulates it, and slows down the burning process. The fire resistance design of Kerto LVL products is conducted according to the EN 1995-1-2 standard and its national annexes. To achieve the fire ratings required for 102 story building, additional fire protection would still be required in the form of sprinklers, and drywall, but many parts of the wood structure could remain exposed. In contrast, the steel structure of the Empire State Building needs to be fully protected by insulation, drywall, stone and other fire resistant materials to provide safe resistance to fire.

Kerto LVL comes only from certified, responsibly managed forests that grow significantly faster than they are used. Four saplings are planted for each tree that we use.

Future

Wood high-rise revolution

We're once again at the beginning of a revolution in the way we build. In fact, this is the first new way to build a skyscraper in the last 100 years. The challenge now is to change society's perception of what’s possible. And these big changes require the same bravery present when the original Empire State Building was proposed.

When the first skyscraper was built, people were terrified to walk beneath it. Significant advancements in engineered wood and mass timber products have created a new vision for what is possible for safe, tall, urban wood buildings. When harvested responsibly, wood is the only carbon-neutral building material that can reduce greenhouse gas emissions and actually sequester carbon for the life of the building. Wood is the structural material that aligns with the innovation required to address the environmental challenges we are facing today.