ROOT-AND-BRANCH REFORM
Using homegrown timber rather than concrete and steel could ease Scotland’s housing crisis and have huge environmental, financial and social benefits for the whole country
Wooden houses could be the future of home building
When you think of building in timber, you inevitably think of Swedish saunas or Swiss chalets. But it’s time we opened our minds and became more continental in our approach to construction.
With a recent report revealing that 150,000 families in Scotland are waiting for social housing, and the Commission on Housing and Wellbeing calling on the government to increase the number of new homes being built to 23,000 per year (from 15,500 in 2013-14), it’s time for a fundamental change in direction.
Building every new house from wood could have far-reaching environmental, financial and social benefits for Scotland. A nationwide commitment to building exclusively in timber could rejuvenate our rural economies and put home-grown forestry at the centre of a growing European industry at the same time as provi- ding much-needed housing at a lower cost. With bruises on rural economies across Scotland only just beginning to fade following an economic battering courtesy of the recession, a commitment to timber new-builds – both social and private – could significantly speed up the recovery while contributing to the Scottish government’s target for all new buildings to be carbon neutral by 2016.
Mass timber construction, specifically from cross laminated timber (CLT), would allow us to make the shift from carbon-concrete to eco-friendly wood. CLT panels are formed from layers of timber bonded together to form large structural panels that are light, strong and well suited to building entire structures quickly.
CLT makers can compete with solid masonry construction techniques while offering far better green credentials, including the use of
sustainable wood, which traps carbon during growth and then stores it in structures. In other words, CLT offers a way of using the built environment as a carbon sink.
Since its emergence in the early 1990s, solid timber construction using CLT has become a well-established building technology across Europe. It is still relatively new to the UK but it is being used for a steadily rising number of projects here, from schools to multi-storey apartment blocks. Among t he latter is t he Stadthaus building in north-east London, which became the tallest such structure in the world on its completion in 2009.
Limitations on size and design and an increased fire risk are among the fear factors when it comes to wooden builds. In fact, one of the major advantages of CLT is its inherent fire resistance – charring on the outer layer acts as an intumescent coating – and unlike steel it remains structurally stable when subjected to high temperatures. Wooden design possibilities can also compete with traditional bricks and mortar, with British architects finally beginning to demonstrate wood’s vast potential.
Given that Scotland is home to more than half of the UK’s trees, building entirely from timber is a concept we should embrace. There has been some movement in that direction, with Edinburgh-based Gaia Group architects completing the much-lauded 1,300m2 Acharacle primary school in the Highlands in 2009 before going on to build Plummerswood House in the Borders in 2011. The latter is the UK’s first Brettstapel home – a building system of cross lamination held together with hardwood dowels rather than glue. It won the Scottish Homes award for Architectural Excellence in 2012, and data collected during a two-year post-occupancy evaluation showed that the building used 30% less energy than a property constructed to the very highest level of the Code for Sustainable Homes.
Larger-scale CLT projects are also cropping up around the country. A new community centre and primary school extension in Kelty, Fife, for example, is being constructed from 6,000m2 of timber panels, and represents the largest CLT project in Scotland to date.
At first sight, the cost of CLT can appear higher than some concrete or steel alternatives, but this is deceptive. The on-site build time will be significantly shorter, cleaner and quieter than traditional bricks and concrete. Increased energy efficiency due to the ‘ airtightness’ of the material adds long-term cost savings and a sustainability conventional methods cannot match. Timber really is coming of age.
Building with a replenishable material such as wood is likely to get cheaper (especially when it no longer needs to be imported), while building with commodities such as steel, whose price has been driven up by insatiable demand from emerging economies such as China, will become steadily more expensive. With the building industry crying out for a cost-effective and reliable source of wood closer to home, the potential growth in demand for home-grown timber is a golden opportunity for Scotland to shine.
Research carried out by Edinburgh Napier University and Forestry Commission Scotland found that Scottish timber is of sufficient quality and quantity to support an economically viable CLT manufacturing plant. And with the Lanarkshire-based construction firm CCG recently investing £4 million in a vast new plant to manufacture strong wooden timbers for the construction industry, home-grown CLT is surely just around the corner. Although CCG will initially import its raw material from abroad, chief executive Alastair Wylie says he hopes ultimately to source all the necessary raw materials in Scotland. The country is already able to supply between 15,000 and 70,000m3 of Sitka spruce wood annually for use in CLT manufacture, supporting valuable jobs and prosperity in remote rural communities.
The call from the Commission on Housing and Wellbeing for radical action to tackle Scotland’s housing crisis could be answered by launching an all-timber building initiative. The Scottish government should lead by example and construct all new social housing from wood. With shorter on-site construction time and zero waste, this would ultimately deliver a reduced bill to the taxpayer while ensuring added value and growth within the forestry industry, as well as jobs in the factories where prefabricated panels for builds would be manufactured.
Developing a massive timber industry would help to achieve every one of the objectives in Scotland’s Forestry Strategy – by reducing the UK’s reliance on imported timber and placing the emphasis on making structurally, ecologically and economically sound buildings from home-grown timber.
The ability to harvest building materials locally – and for it then to grow again – is one of Scotland’s huge natural advantages. Increasing domestic demand for timber products through a commitment to wooden builds, and meeting it by growing and harvesting the raw material ourselves, offers environmental, recreational and economic benefits for the whole country, with no great downsides – unless, that is, you are in the structural-steel and concrete business of course. If you are, maybe now is the time to ‘branch out’ into timber panels.
‘The onsite build time will be significantly shorter, cleaner and quieter than traditional bricks and concrete’