Well-connected

Summary
• In Touch with Timber took place at London’s QEII Conference Centre on May 19.
• More than 200 construction industry professionals attended.
• Timber’s carbon saving credentials were explored.
• Thermal mass can be achieved using engineered timber such as CLT.

TRADA’s fifth In Touch with Timber conference proved to be a forum for positivity in the face of economic disorder. For starters, delegate numbers at the May 19 event hit an impressive 200-plus architects, engineers, specifiers and construction industry professionals. And the programme provided them with plenty of reasons why they should be working with timber.

“The conference is all about inspiration, but the speakers also present commercial arguments for using timber,” said TRADA’s chief executive Andrew Abbott in his opening address. “There are many positive messages, despite the current ‘rough patch’. It’s easy to talk the market down, but as the industry climbs out of recession, there will be excellent opportunities.”

And, he added, a compelling reason for specifying the material was its environmental credentials. “Ecological building materials are becoming mainstream and in this respect timber has an enduring appeal.”

Carbon credentials

For two speakers in particular – Simon Smith, design director at structural engineers Ramboll UK, and Mark Sowter, former head of environmental construction at Tesco – timber’s carbon-related environmental credentials should be made to count for more.

General perceptions of timber had to be changed on two counts, said Simon Smith. The first was a simple matter of scale. “We [Ramboll UK] are working on projects of 10,000m² or more, but that’s rare – we need to change the perception of the scale of projects which are possible in timber.”

The second count was also numbers related: “We need to address the environmental reporting of timber,” he said. “We all know it’s green, but it needs to be backed up by numbers.”

The lack of convincing legislation encouraging specifiers to choose timber was also a handicap, he said. “We want to give clients a reason to choose timber, but there’s no legislation that really allows us to do this.”

Despite a zero carbon target from 2016, the government’s June 2008 strategy for sustainable construction report’s only specific reference to materials was in the disposal of site waste, said Mr Smith. “There is no mention of the choice of materials, just that reference should be made to the BRE’s Green Guide to the specification of materials.” And here again, the environmental weightings for materials and waste are lumped together.

The government’s Code for Sustainable Homes showed “some light at the end of the tunnel”, he said, but its reluctance to investigate the issue of embodied carbon levels was “very disappointing”.

The figures that count

“Timber and embodied carbon is what we should be talking about. There are two issues around carbon [in building] – embodied energy and operational energy. [Traditionally] about 20% of a building’s carbon is embodied and 80% is operational, but we now have buildings where the ratio is more like 60:40,” he said – and it’s these figures that should be made to count in timber’s favour.

The life cycle for a cubic metre of timber from forest, through processing, to construction and finally to being burned for energy production, results in 275kg of CO₂ emissions, as opposed to the equivalent amount of concrete’s 1,000kg. “If we can take embodied carbon into account then there is no other competing material,” said Mr Smith. “If you’re building with renewables it takes about 20 years to get a carbon saving – if you build with timber you get it now. Government and local authorities have to be made to understand this.”

Mark Sowter agreed that trapping carbon in buildings has as much, if not more, environmental value than renewable energy systems, but that for Tesco, whose primary concern is keeping its customers happy, perceptions count for a great deal.

For example, the wind turbines that top Tesco’s new “eco-stores” are more iconic than functional but are associated with being green and enhance the retailer’s reputation as a result, he said. “That’s the world we live in.”

A green triple bottom line

Having said that, green issues underpin Tesco’s triple bottom line. In economic terms, buildings must be simple and repeatable, with an eye to keeping capital costs low – hence the stores are designed for low maintenance and low U-values. In environmental terms, sustainable materials, embodied carbon and carbon emissions are the watchwords. And in social terms, a greener building provides a better working and shopping environment.

Tesco’s latest eco store, which opened in January at Cheetham Hill in Manchester, features a glulam frame and is targeting a 70% reduction in carbon emissions which, in turn, will significantly reduce operating costs. It is 49% more efficient than other Tesco stores and is contributing to the retailer’s goal of achieving a 50% reduction in CO₂ emissions across its estate by 2020. “The overall capital cost was 10% more, but the embodied carbon benefit [of using the glulam frame] was 20%, giving us a 10-year payback on current energy prices.”

“Buildings are becoming more complicated in the way they operate,” said Mr Sowter. “Services are more important than anything – designing them in at the outset is absolutely key to reducing carbon emissions.”

Communicating the message

What was also crucial, he said, was to “help the end users understand what they’ve got”. “Most people’s experience of a timber building is their garden shed – and they think they can catch fire easily,” he said. So it was important to communicate the message that, not only was timber an environmentally-friendly construction material, but that timber buildings were robust. That could be proved by monitoring how they stand up to everyday use.

Keynote speaker Alison Brooks, director of Alison Brooks Architects, supported the view that timber buildings were robust.

The Canadian-born architect, who “grew up with timber being the norm for building”, gave delegates an insight into several of her award-winning projects, including the Salt House in St Lawrence Bay in Essex.

Its waterside location immediately suggested “a timber building on stilts”, but while Ms Brooks resisted the latter, she stuck with timber, despite the house’s brick-built neighbours. “It’s a very robust construction with marine ply used extensively inside and the outside clad in ipe. A lot of the principles we used here could be applied to building in flood plains.”

Using timber, she added, resulted in “affordable, spacious and quality homes”.