Respected certification schemes offer one route to ensuring wood is from sustainable forests. But at the recent Timber and the Built Environment conference in Edinburgh Forestry Commission director-general David Bills pointed out that not all wood from well-managed forests is or ever will be certified. “So there probably will always be a need for purchasers and specifiers to have an intelligent or well-informed approach to their choice of timber. It would be a pity if uncertainty of the provenance or origin of wood influenced specifiers to favour non-wood substitutes which themselves propose environmental problems.”

Illegal logging

According to Mr Bills, an estimated 15% of the global trade in timber and timber products is illegal while some logging operations are “clearly unsustainable” even though they are sanctioned by the relevant authority. At the same time, a substantial volume of wood coming into the UK from well-managed forests is not certified.

“There is a lack of capacity to arrive quickly at a position where wood from well-managed forests is certified,” said Mr Bills. “Furthermore, wood from some developing countries is coming from quite well-managed forests but the institutions, the systems, the documentation and the chain of custody are not in a form or not well enough developed to be certified.” If this such wood isn’t used it “would penalise a developing country” and to use a non-wood substitute instead “could penalise the environment”.

Mr Bills anticipated an increasing number of specifiers taking more interest in the provenance of their timber. This point was underlined at the conference by John Gilbert of John Gilbert Architects, who maintained: “There is a frustration among architects in not knowing always where the timber is coming from. We need to go and find out.”

The conference was held a few hundred metres from Edinburgh Castle at The Hub, which was originally built as the headquarters of the Church of Scotland. Abandoned in the late 1980s, restoration of the building included replacement of earlier steel repairs to the roof with a timber-based solution.

Timber preservatives

Among other speakers at the conference, Ivor Davies highlighted what he described as the “severe” overuse of timber preservatives in the UK. Formerly with Highland Birchwoods and now an independent timber research consultant, Mr Davies insisted: “Over half of the CCA used in Europe is used in the UK and there is no justification for that. I am not against preservatives – wood preservation is essential in some instances – but there are a lot of instances where it has been over-used”.

Mr Davies went on to note that UK wood production was expected to increase from around 9 million m3 at present to more than 16 million m3 over the next 20 years. With a large proportion of this increase expected to comprise medium- and low-grade softwoods, “the challenge is to find uses within the construction industry,” he explained. “Only 22% of UK timber is currently sold into construction and a lot of those markets are declining, and so we need to find new markets in construction.”

He pointed to the success of James Jones & Sons in selling its light but strong I-joists into the housebuilding market and to the firm’s plans to more than treble production at its Forres factory in the foreseeable future. This product was benefiting from its availability in “very long lengths”, he added.

Timber frame successes

Mr Davies also hailed timber frame as “a major success story in Scotland” with a more than 60% share of the low-rise housing market north of the border compared with around 6% in England and Wales. Later in the day, Stewart Milne Timber Systems (SMTS) managing director Stewart Dalgarno outlined the company’s plans to widen market penetration of timber frame south of the border where, according to his own figures, less than 10% of the 170,000 new houses built each year were of timber frame construction. There was a clear need, he said, to educate people in England and Wales about the benefits of using timber.

SMTS had invested £10m in a new factory in Oxfordshire, where the company was looking to adopt a car assembly line approach to timber frame construction. The drive towards computer data transfer, automation and even robotics has already meant that there are no longer any drawing boards at Stewart Milne, he noted. Structures were also becoming more engineered, he added.

According to Mr Dalgarno, who is also vice-chairman of the Timber Frame Industry Association, the future might even bring fully factory-finished timber frame panels – a development which would dovetail with the trend towards fewer skills being available on site and the increased emphasis on health and safety.

Home-grown opportunities

Timber frame provided an opportunity to use large quantities of home-grown as well as imported timbers, added Mr Dalgarno. SMTS, for example, had recently secured a major project with a holiday company that would entail using “major volumes of home-grown material”.

Dr Peter Bonfield, director of the Centre for Timber Technology and Construction and director of the Centre for Composites in Construction at the BRE, argued that innovations such as the climate change levy and landfill tax had ensured that, from the industry perspective, the environment was no longer “an ethereal debate”. BRE studies of the environmental impacts of a range of construction materials had yielded positive results for the timber sector. “In almost every construction element, timber comes out very favourably,” he told delegates. “We shouldn’t feel bad about using wood because wood is good.”

The ‘ecopoints’ database constructed by BRE reduces all environmental factors to a single number that enables project leaders to modify plans in order to achieve the best balance between cost and the environment. “In general, if you reduce the environmental impact, you often reduce the environmental operating costs,” Dr Bonfield explained. While it had often been felt in the past that adherence to environmental principles would naturally lead to a higher overall project cost, “we have found that that is not necessarily the case,” he added.

Director of BRE Scotland Dr Stephen Garvin had earlier outlined the possible impact of climate change on the timber industry. He pointed to latest estimates that the UK climate would become between 2-3.5OC warmer within the next 80 years; other prospects included higher rainfall, more frequent hot summers, more intense winter precipitation events and more frequent storm surges.

Increased pest risk

With help from the UK Climate Impacts Programme, BRE has produced a report that identifies the potential impact of climate change on buildings. The main area of concern for timber construction is that warmer temperatures could encourage some pests in the UK and the spread of existing colonies of damaging pests, notably house longhorn beetles and termites. Dr Garvin urged the development of best practice guidance relating to pests and also recommended, for example, design of ducting to prevent free movement of pests and requirements to use pest resistant materials.

According to BRE, other potential timber-related impacts of climate change include weather tightness of doors and windows, and faster deterioration of glazing materials in joinery; deterioration of paints and coatings on timber joinery; flooding on timber ground floors, including risks associated with new level access thresholds; increased moisture attack on external timber joinery; and increased risk of internal condensation resulting in durability problems.

Dr Garvin told delegates: “The timber industry has a responsibility to respond to climate change for the structures we have.” Scoping research conducted by the BRE needed to be followed by structural programmes to address, for example, durability of materials and the effects of increased flooding, he added.