Tall towers are not the answer to environmental challenges: Andrew Waugh

GUEST OBSERVER

If you gave ancient Romans iPhones, it would blow their minds… but if you took them to a modern construction site they would get it – for, thousands of years ago, they too built in concrete and brick as well as stone.

Today, about a third to half of the carbon emissions associated with a building over its lifecycle comes from creating the materials used to build it, but developers, builders and architects have been reluctant to change.

The solution doesn’t have to be invented. It already exists, in the form of modern engineered timbers. Unlike conventional materials, sustainably sourced engineered timber actually stores carbon. Engineered timbers are also cheaper, faster to build and can be pre-cut in factories, so there is less time lost to weather and safety risks are easier to control. The resulting buildings are sturdy, safe and well insulated.

In a world where housing affordability is an issue, where homelessness is a problem and where climate change is a real threat, I see engineered timbers in mid-rise apartments as being the future of building in urban areas.

Compared to tall towers, mid-rise building in cross laminated timber (CLT) – sometimes referred to as plywood on steroids – has a number of environmental advantages.

Tall buildings are highly inefficient. When you’ve got a tall tower, you’ve got to pump water up great heights, you need cooling as there’s no natural shade and they’re also often badly insulated and acoustically poor because developers cut costs by building in lightweight materials.

And a whole lot of tall towers together leads to poor urban spaces, which would be far better built at between seven and 12 storeys.

The problems are not just practical. We’re living in an age where many architects strive to achieve a design that is amazing, incredible and completely different – (translation: they draw a funny shape and give it to an engineer to work out how to build).

Sometimes it’s better to keep it simple, and make sure that the bedroom has a window and that you can get to the staircase and so on. Simplicity can have its own beauty, particularly when you’re building in timber. Architects also need to think about the construction material and incorporate this in the initial design stage.

In the UK, there are now about 500 buildings made of CLT, including civic spaces, schools and housing complexes. That number is set to explode.

There are currently three factories on the drawing board that will create modular CLT housing in the UK alone, and the largest of these is being designed to produce 5000 homes a year – at a cost of about 20 per cent cheaper than conventional materials.

I’ve also designed the world’s largest (by volume) CLT housing complex, Dalston Lane, in the UK, which is currently under construction. The ten-storey, 121-unit development is made entirely of CLT, from the external, party and core walls, through to the floors and stairs, weighing a fifth of a concrete building of this size, and reducing the number of deliveries during construction by 80 per cent.

Meanwhile, the record for tallest mass timber building – containing engineered timbers other than CLT – is constantly growing and currently sits at around 18 storeys in height.

In Australia, CLT has been successfully used, but is not as common as in the UK. That may change with a recent update in the construction code making it easier to build mid-rise CLT buildings – and with the imminent opening of Australia’s first CLT factory, meaning the material will no longer have to be import_ed.

There are a number of ways governments can help promote the use of timber, including:

Policies promoting a reduction in carbon emissions from buildings – regardless of building material

Timber first policies, which are used in many countries to ensure that timber should be considered as a building material in any public building project before design begins

Commissioning public buildings, including social housing, in engineered timbers to help increase industry knowledge and support local manufacture of CLT

Introduction of a carbon tax

However, in the UK, CLT has taken off without much in the way of government promotion because the business case for it is so compelling, and the environmental benefits a bonus.

Andrew Waugh is a founding director of Waugh Thistleton and can be contacted here.