Wood you live in a skyscraper made of trees?

Probably would pass on the penthouse suite if this was made of wood. Picture via Pexels.

 

Every child dreams of living in a tree house. But most children don’t realise they already do. Their parents are just too scared to politely inform them that the scaffolding of their beloved family home is actually made from dead trees. Then again, explaining that a house made of wood is effectively ‘tree bones’ isn’t G-rated, nor is it as romantic as Enid Blyton’s “Magic Faraway Tree”.

I still think it’s pretty magical though. Nature has given us a durable construction material which ostensibly appears from nothing. Simply pop a seed in the ground, wait a few years later, and wallah! – a solid mass of strong, flexible fibre has grown before your eyes.

Wood has been used in construction for as long as humans have constructed. But the industrial revolution brought stronger and more durable materials to the fore, namely steel and concrete. These two materials now reign supreme, especially within superstructures like bridges and skyscrapers. Although wood is still in circulation, it has been relegated for use in smaller structures such as in housing and landscaping.

But there’s a big problem: sustainability.

Manufacturing a tonne of cement – a key ingredient in concrete – releases a tonne of CO2 into the atmosphere. The cement industry is consequently responsible for 5-6% of anthropogenic carbon emissions. As for steel, it is a highly recyclable product and very durable. Yet being an alloy of iron and carbon, it is not a renewable product. Additionally, iron ore mining is an energy intensive process.

An iron-ore mine in South Africa. Steel may be a strong and durable material, but it’s not renewable. Photo by Media Club via Wikimedia Commons.

As such, environmentally conscious engineers and architects are shifting their focus back to the original building material: wood.

Wood is carbon neutral and renewable, provided its harvest is offset by the planting of a new tree in its place. As trees grow, they sequester carbon from the atmosphere into the solid form of wood. A piece of dry wood is 50% carbon, and this carbon remains locked away in the wood throughout its lifetime. Growing timber and locking it away in built structures can be seen as a carbon sink.

Traditionally however, wood has not been the best material for large buildings such as skyscrapers. Firstly, it is flammable. You wouldn’t want a small mishap in the kitchen to bring down an entire apartment block. Secondly, it is not as strong as as steel. And thirdly, it is not very malleable and is difficult to use in designs requiring curved supports.

Yet recently this has changed. Enter our material heroes: Cross-Laminated Timber (CLT) and Glued Laminated Timber (Glulam).

A close-up of CLT. It is a compressed sandwich of wooden blocks glued together in alternating directions. Photo by USDA via Flickr.

Both of these materials are made from laminated layers of wood, which makes them stronger and suitable for heavier loads and longer spans. They can also be prefabricated into a variety of ready-to-use shapes, giving architects creative freedom while dramatically cutting construction times.

Australia’s largest wooden building was recently completed in Brisbane, and it’s an impressive sight. Given its sustainability, architectural charm and ease-of-construction, the building’s developer – Landlease – has committed to using timber in all of its future building projects.

It looks pretty regular, but the Brock Commons in Vancouver is the world’s largest wooden building, at 53 metres. Photo by UBC Media Relations via Flickr.

This is good news for the climate, very good. A Yale University study estimates that 14-31% of global CO2 emissions could be avoided by transitioning back to wood buildings.

So let’s get planting.


7 Responses to “Wood you live in a skyscraper made of trees?”

  1. Ashley Densham says:

    Cheers Lydia, glad you enjoyed.

  2. Ashley Densham says:

    Absolutely Romy, any move towards a greater use of wood needs to be accompanied by responsible systems of harvest and distribution. Thanks for reading 🙂

  3. Ashley Densham says:

    Thanks Gary. Totally agree. The reality we must face is that wood comes from trees, and we’ll have to cut them down at some point if we want to utilise this sustainable material. As long as we implement a system of responsible harvest and replanting we can make it work!

  4. Gary Yang says:

    A lot of people are against using wood, and I think this comes from a lack of understanding about plantations and carbon sequestering. It’s so good that you’re informing people about the sustainability of this building material!

  5. Gabrielle Stinear says:

    Great title and an even better article, I was hooked straight away!

  6. Romy Lipszyc says:

    I love this! I’ve been signing petitions for more buildings made from sustainable wood for years. I think that this plan is brilliant, except we should be cautious of planting native trees for use in particular countries, and for the potential removal of habitat from native flora and fauna.

  7. Lydia says:

    Wow! What an interesting read. I’d never thought about this as an environtmentally friendly building material. Keep up the good work :))