The Sky's the Limit

As touched on previously, despite the historical use of timber in our society there has been an apprehension of large timber structures, particularly following large fires that plagued societies in the past. Furthermore, increasing population sizes led to increased urbanised areas and greater population density, meaning architecture was stretched to new heights. Catalysed by the industrial revolution, taller buildings previously made from stone or masonry, could be erected far faster and to new heights.

Home Insurance Building constructed up to 12 stories using steel in Chicago (1884)

Source: Wikipedia

However, as the industrialisation trickled into other industries, the timber trade was reinvigorated with a spate of new technologies as covered here. As such the perception of timber is changing around the world, and so is the policy governing its use.

In 2017, China law changes that would increase the potential applications of timber. It directly increased the allowable height of buildings made using timber as the primary structure up to 5 floors (GB/T51226). Furthermore, it would allow for up to 18 stories to be constructed with certain approvals from local authorities. Another more general directive (GB50005-2017) came into effect in 2018, which would encourage the research and use of timber within the country.

On the other hand, the UK banned the use of combustible material in external wall panels in 2018, following the Grenfell fire in which many died. This was initially labelled as a knee-jerk reaction particularly as it not only applied to the cladding material, which was at fault in Grenfell, but also the wall itself, which can easily be protected from fire. As such, there is ongoing review and a petition to determine how this can be adjusted, however in its current state, timber buildings can only use CLT on the exterior walls up to 18m high. This can be seen with generally lower rise buildings popping up, such as Google’s new London HQ near Kings Cross.

Source: Ricardo Foto

In a dramatic contrast, Mjostarnet (pictured above) was erected in Norway, currently holding the crown as the tallest timber building in the world. It stands at 85m tall, approximately 18 stories, and is composed of both glulam and CLT, mostly sourced from nearby spruce forests. And it’s not alone, the HoHo Tower under construction in Austria aims to reach 84m tall, and Brock Commons in Vancouver topping out at 53m, however both of these are designed with hybrid structures, utilising concrete elements for the cores.

Mjostarnet under construction, with the glulam beams on show

Source: New Atlas

More recently, Ursula von der Leyen even touched on the potential it holds in the European Parliament State of the Union Address, as part of a push to cut carbon emissions by 55% by 2030.

Even the UK Climate Change Committee published a report on how an adoption of timber construction for housing and low rise homes could be an effective contributor to the UK’s carbon abatement strategy.

Timber is clearly starting to find its place in our urban environment, however in my future posts, I’ll start to scrutinise just how sustainable it can be.