March 18, 2013

Original Source: Strombo (CBC)

Vancouver-based architect Michael Green has a radical idea for skyscrapers: he thinks we should build them out of wood, not steel and concrete.

Green recently delivered a talk at the 2013 TED Conference about using wood to build urban skyscrapers and multi-family structures.

He’s been exploring the possibilities of building large urban structures with wood for a while. Last year, he released a feasibility study called ‘The Case for Tall Wood Buildings’.

His case is mainly based on sustainability. Green says “the building industry in North America has a footprint larger than any other industry when it comes to energy.”

Most of those structures are built from steel and concrete. And those materials take a heavy toll: three per cent of the world’s energy is consumed by steel manufacturing, and five percent goes to making concrete, according to The Atlantic Cities.

Green says there’s another material available, and it comes from nature. According to his presentation, enough trees to build a 20-story skyscraper grow every 13 minutes.

With an estimated three billion people expected to move into urban centres in the next few decades, more sustainable building practices will be an important part of accommodating them all while limiting environmental damage.

But the idea of skyscrapers built out of woods definitely raises some eyebrows. Green says the first question he usually gets asked is, “what about fires?”

Not a problem, apparently. The wood used in modern skyscraper construction is based on super-compressed mass timber panels, with buildings crafted from giant blocks which are very fire resistant.

Plus, Green says the construction techniques developed by his architecture firm are also safe for earthquake zones.

The idea of a skyscraper built out of wood may sound a little far-fetched, but it’s getting close to reality in a couple of places.

Vancouver is currently reviewing Green’s proposal for a 16-20 story tower, and Sweden has already approved a 30-story wood tower.

According to Green, the engineering problems associated with using wood to build towers have already been solved. It’s perception that has to change.

“Shifting our minds is the challenge, not shifting the engineering,” Green says in his TED Talk. “The engineering and the science exist, but we need to move beyond what we think is possible and try things.”

On a side note, there’s a city in Yemen called Shibam that is home to the world’s first skyscrapers – made out of mud.

There’s about 500 of them, made from mud mixed with chaff and hay. They’re five to eight storeys, up to 130 feet high, and several hundred years old.

The towers are a Unesco World Heritage Site, and the city has become known as the Manhattan of the Desert.

About 7,000 people live in the community, which is surrounded by a wall. The buildings have survived heat of 45C (113F) and flooding, and some are whitewashed with lime to slow down erosion.