It has all the ingredients for a perfect marriage. British building is using more wood and, over the next couple of decades, British forests will be producing ever greater volumes of it – in fact, the Forestry Commission (FC) expects the harvest to double by 2025. The only hitch is that 80% of the increase will be Sitka spruce and, the trouble with this is, because it grows so quickly in the UK’s clement climate, the quality to date has been unpredictably varied. The traditional preference for construction timber has been more uniform, slower grown softwood from the chillier Nordic countries and North America.
Romantics will be happy to hear however, that the marriage may yet be on, with researchers at the Centre for Timber Engineering (CTE) in Edinburgh striving to bring British timber and construction together through a number of development projects to boost native spruce quality and durability.
Part of Napier University’s School of the Built Environment, CTE was launched in 2003, but is already highly regarded by its peers and the wider world. In its first year the Scottish Higher Edu- cation Funding Council demonstrated its regard by awarding £1.2m funding for CTE’s Strategic Integrated Research in Timber (SIRT) project.
The four-year programme has an ambitious aim – to establish the UK as the world centre of expertise on Sitka spruce. It will first identify variations within the species across the country and then analyse the role this played by factors such as provenance, climate and environment. While CTE contributes the engineering expertise, the FC’s Forest Research will provide knowledge on tree growth and forest management, and Glasgow University will focus on the molecular research.
The end result should be a scientific system for selecting Sitka spruce for construction quality using a range of tools, including:
• non-destructive sonic and ultra-sonic testing;
• finite element modelling, verified against a scientific and engineering knowledge base;
• statistical energy analysis to predict and analyse the vibration behaviour of timber
structures.
The SIRT programme is similar to one carried out in South Africa for eucalyptus. Playing a key role in that was the CTE’s director, Professor Philip Turner. Before taking up his current post in September 2005, he was director of the Forest & Forest Products Research Centre at the South African Council for Scientific and Industrial Research (CSIR).
“With eucalyptus we had huge variations. People didn’t have a concept of what problems could arise at the mill – it literally upset the industrial process,” he said. “One of the biggest challenges for processing industries throughout the world is to produce a consistently high quality product. This is thwarted by the variability in the timber resource and the lack of understanding of the extent of the variation and what drives it. The goal is to channel the right material into the right process so you have consistent quality.”
Turner is confident that the SIRT is about to gather pace. “The first part, looking at genetic variation, is almost complete. The data is being analysed and should produce some interesting results. Now we’ll start fast-tracking and my experience in South Africa will help speed things up.”
CTE also has other home-grown timber projects on the go. Research fellow Ivor Davies, for example, has been working on external timber cladding in maritime conditions. This three-year, £700,000 study has looked at the effects of wind-driven rain on various cladding types in the Scottish Highlands and Islands.
Again, CTE is working with partners. BRE is researching the material properties of spruce and their effects on performance and cladding as well as the variations in fungal decay; Forest Research is mapping driving rain conditions; while CTE is examining the impact construction detailing has on moisture conditions in timber cladding and on fungal risk. And the programme also involves research partners undertaking similar work in Norway, the Faroe Islands and Iceland.
“The idea is to help specifiers and designers produce the best type of cladding and address the question of whether Sitka spruce can be used as a cladding material, like Norway spruce which is a standard in Scandinavia,” said Turner.
CTE’s professor of timber engineering, Abdy Kermani, has been working on the development of the composite insulated beam (CIB), which comprises timber flanges, and double webs of OSB or plywood insulated with a rigid infill of urethane or expanded polystyrene in a sandwich construction.
The beauty of the CIB is that the rigid thermal insulation prevents cold bridging in buildings and makes the beam dimensionally stable. Because it improves its structural performance, relatively low-grade timber, such as Sitka spruce, can be used to produce a top quality engineered product.
The CIB has now been patented and Scottish Enterprise has provided “Proof of Concept” funds to help bring the product through to commercial production. “The hunt is on for
an industry partner to place the CIB on the market, hopefully within the next six months,” said Kermani.
This goal of commercialising leading edge technologies is just one example of CTE’s pragmatic approach. Another is its role as an education provider.
“It’s important to have an integrated research strategy that takes account of industry needs, and these are fairly broadbased, from growing and harvesting, through to processing and end use,” said Turner. “It also requires that we say what the human resource profile is and deliver on that.”
CTE’s undergraduate and postgraduate programmes have been designed around the needs identified in the forestry, timber and construction industries and some of its students play an active part in its research.
The knowledge transfer role also goes further than the degree courses. A £650,000 project, part-funded by the European Social Fund, entitled Timber Engineering Online (TEO), has the capacity to deliver “flexible learning” and address the UK’s wider shortage of timber building design expertise.
The online education facility will enable CTE to provide diploma and degree courses and continuous professional development (CPD) credits through a range of timber-oriented modules. The latter are currently being piloted and some will be launched this year.
“Online teaching is expensive for the provider,” said project co-ordinator Dr Sabine Nolte, “but the different levels of teaching TEO provides make it more cost-efficient.”
CTE’s across-the-board approach means that, while students might find themselves in careers which demand CPD top-ups, similarly a professional buying a 10-hour CPD programme relevant to their job may be enticed into pursuing a degree course. These online units are embedded in the Masters courses and carry credits which count towards the appropriate qualification.
“We’re no longer in an environment where it’s school-degree-job,” said Nolte. “We’re now learning throughout the job as well, otherwise we can’t keep up.”
Producing the timber engineers of the future is vital, but Turner believes it’s just as important to educate tomorrow’s captains of the timber industry on the importance of innovation and the role research plays in innovation.
“There is often a temptation to make existing technology work as efficiently as possible and make it short-term focused on making money,” he said. “But if we don’t stay fairly close to
the cutting edge, we’re going to be out. Any business that wants to be there for the long haul needs to understand the competition – and the competition is driven by technology and innovation.”
