A new wood Architecture

14 March 2013

Engineered timber building is forging onwards and upwards but, longer term, other ways of exploiting wood’s construction potential will be needed, says Simon Smith of engineers Smith+Wallwork, as, says Andrew Waugh of architects Waugh Thistleton, will a stronger home-grown timber construction sector

THERE SEEMS TO be little slowing down of our thirst for all things wood in UK construction. According to the Office for National Statistics, we imported over £0.6bn of sawnwood in 2012 and, while there are no precise figures for engineered timber (namely glulam, crosslaminated timber and LVL), the consensus is that demand is growing.

The 'Wunderkind' of the industry is cross-laminated timber (CLT). European production last year grew 25% to nearly 500,000m3, and by 2015 that could double. The UK market is still small at 25,000m3, but is projected to grow at a similar rate.

CLT's success lies in simplicity and robustness, and the fact that you can build a 10,000m2 weathertight structure in 16 weeks. The construction sector is also discovering its possibilities for high-rise. As one of the least densely wooded EU countries, it is probably not surprising that the UK was the first to go tall with timber in the form of the nine-storey CLT Murray Grove in London (see p9). The lack of timber culture means we're free of the constraints of precedent, a culture shared with Australia, which recently stole the tall timber crown with Melbourne's Forte building. But now the wooded nations themselves are heading for new heights too; Canada with Michael Green's 30-storey tower, Austria with the Life Cycle Tower and Timber in Town, Finland with Wood City, Italy with Via Cenni and Sweden with the Strandparken project in Stockholm.

The potential for the UK to do still more with wood building is clear. With per capita timber consumption rates significantly lower than many parts of Europe, we are nowhere near saturation. We are also in the midst of a bumper wood harvest in the UK, thanks to reforestation from the 1950s to 1980s, and our universities (Edinburgh Napier University and the University of East Anglia) are now coming up with the research and test data to stimulate new uses for homegrown material, such as CLT (see p18) and Brettstapel (see p19). In addition, timber has the opportunity to seize on increasing environmental regulation, including the introduction of the 'Sustainable use of natural resources' to CE marking (part of the Construction Products Regulations) and the establishment of environmental product declarations.

Combine this with UN predictions that the UK population will outgrow Germany's by 2060 and surely the only way for wood is up (quite literally).

So where is the main potential for UK wood building? The residential, sports and education sectors have historically hoovered up structural timber but we're now starting to see its use in health and retail schemes and offices. Many of these are larger scale projects in densely built urban environments where there's a need to build taller.

In addition, timber cladding could increasingly be used to reduce the urban heat island effect, replacing thermally massive brick and concrete.

But such an increase in timber consumption requires a rethink about efficient manufacture, design and end of life. If timber is to gain construction market share over the next 40 years, at the same time as demand for building materials is set to double, we can't just rely on Europe's expanding forests to generate ever greater supplies of wood.

With modern engineered products, timber has truly arrived in the urban environment and corporate jungle and CLT presses so many buttons, delivering robust flat pack buildings in super quick time and locking in so much CO2. But some argue that it would be better to use the same volume of wood to deliver twice as many buildings. While, it could be used to replicate steel and concrete monoliths, perhaps the real scoop would be a new wood architecture driven by the progress in timber processing, manufacture and sustainable design.

Advances in materials driving new architecture movements have been seen before; concrete and brutalism in the 50s, steel and hi-tech in the 70s. What could wood do?

With the UK’s growing population the only way for timber construction is up PHOTO: PATRICK FLEMING
We’re now starting to see the use of structural timber in offices, health and retail projects PHOTO: PATRICK FLEMING
Melbourne’s 10-storey CLT Forte building