Summary
• More than 140 people attended the Wood Futures conference at the Royal Festival Hall on November 6.
• The government has set targets of 2016 for zero carbon housing and 2019 for non-domestic buildings.
• The government’s definition of zero carbon should be published soon.
• The built environment accounts for 45% of the UK’s carbon emissions and domestic stock contributes more than half of that.
• The Zero Carbon Hub was established five months ago to help to deliver low and zero carbon housing.

While the government’s definition of zero carbon is eagerly awaited – and overdue – housebuilders and their supply chain are wrestling with the concept of just how to build zero carbon houses.

Evidence of the interest in this goal was seen at TTJ’s Wood Futures – Countdown to Zero conference at the Royal Festival Hall on November 6. Sponsored by Medite 2016 and supported by TRADA and The Timber Trade Federation, the event was attended by over 140 delegates, covering the supply chain from sawmillers, through merchants, to architects and housebuilders.

The motivation for the government’s zero carbon goal was outlined by Bob Ledsome, deputy director, head of the Climate Change and Sustainable Development team at the Department of Communities and Local Government (CLG). He kicked off proceedings with the all-important statistics. The built environment produces 45% of the UK’s carbon emissions, he said, with domestic housing accounting for 27%, making it the second largest polluter behind transport.

Zero carbon definition

While the government has set a goal of all new houses to be zero carbon by 2016, it is still working on its definition of zero carbon, but Mr Ledsome announced it is due out for consultation soon. However, whatever the definition, it will measure only the building’s energy use performance, not the energy embodied in its materials. “We’re not tackling embodied energy because we thought we already had a big enough task in terms of building energy performance,” said Mr Ledsome.

Thanks to timber’s low embodied energy, this was an approach that clearly frustrated some delegates. But Mr Ledsome added that the government “may come back to it later”.

To help in the “delivery of low and zero carbon homes” the government and industry launched the Zero Carbon Hub, a public private partnership, five months ago. Hub chief executive Neil Jefferson said the government’s goal would require “an unprecedented step change” but his organisation would “provide leadership and confidence, reduce the risk, clear obstacles, and disseminate information”.

The end result had to be faultless, he added, and there was still a long way to go. “Zero carbon homes have to be right because if they don’t perform, there will be no consumer confidence,” he said.

Carbon footprints

With the government having recently upped the zero carbon ante and raised its target for reducing carbon emissions to 26-32% by 2020 and 80% by 2050, besides coming up with zero carbon homes, there is more pressure on construction and related businesses to reduce their own carbon footprint by cutting energy use, said Francis Rottenburg of the Carbon Trust.

While cost and regulation would encourage companies to act, the two big drivers were reputation and competition. “Companies will increasingly be asked about their own carbon footprint,” he said. “It could determine whether business is won.” But, he added, shrinking carbon footprints does bring instant financial returns.

Wolseley plc is contributing to zero carbon construction with its Sustainable Building Center (SBC) in Leamington Spa. Opened this year, the glulam-framed building showcases some of the company’s more than 7,000 products with sustainable characteristics. “This is practical sustainability,” said Wolseley head of sustainability Tim Pollard. “All the products we used had to be available in commercial quantities – nothing that’s ‘Tomorrow’s World’.”

Wolseley’s goal is to display the life cycle analysis (LCA) of every product at the SBC – which is where it had a word of warning for timber. While acknow-ledging that it is “by far the most sustainable construction material”, Mr Pollard said he was “staggered” by how little some timber companies knew about their products’ environmental credentials.

Practical application

Insight into the practical application of zero carbon building was given by Dr Paul Newman, technical director of Kingspan Off-Site, and Ben Cook, senior land manager at Barratt Developments.

Kingspan Off-Site’s Lighthouse at the BRE Innovation Park achieved level 6 of the government’s Code for Sustainable Homes (CSH), and the company’s TEK building system is being used by Barratt on the Hanham Hall Carbon Challenge site in Bristol.

Kingspan’s experience at the latter shows how the supply chain is changing “dramatically” to meet zero carbon targets, said Dr Newman. As an example, it worked closely with JELD-WEN to develop windows for the development and, through its code assurance scheme, it is helping contractors meet CSH requirements.

Ben Cook also emphasised the importance of supply chain partnerships in meeting the carbon challenge. “Without the likes of Kingspan and JELD-WEN working together I don’t think we would get any further,” he said.

He added that achieving zero carbon construction also demands that best practice is shared and he even put Barratt’s Carbon Challenge bid on English Partnership’s website. “My colleagues wondered why I was sharing information, but it’s what we have to do,” said Mr Cook.

Hanham Hall met the Gold standard of Building for Life, the body dedicated to improving UK home design and quality. It was just as well since Wayne Hemingway, chair of the organisation, as well as founder of HemingwayDesign, was also a Wood Futures speaker.

Mr Hemingway attacked much of Britain’s new housing from the last 40 years. “There are very few developments I would have brought my kids up in,” he said.

Social sustainability

He maintained that the sustainability people associate with low-energy technologies should be a given, as they are in other countries. What is really vital is social sustainability. “Without that you can stuff zero carbon. It’s social sustainability that leads to a sustainable lifestyle.”

His ethos was about building communities and pleasant places to live rather than “ticking idiot boxes”.

“We buy homes that have condensing boilers and then forget about things outside,” he said, illustrating his point with a shot of a characterless, drab development furnished with five shabby plastic “springy chickens” as the sum total of children’s playground equipment.

Rupert Scott, TRADA’s building regulations and codes consultant, addressed the role of waste in the carbon equation, and found timber’s record wanting. “Timber does grow on trees but today that’s not enough,” he said, pointing out that the steel and aluminium industries scored better with recycling. And a material’s reuse or recycling potential was something procurement officers considered, he said.

Offsite construction is one way of reducing waste and making it easier to sort and, although there is some conflict between the sectors on pricing and subsidy, wood energy and the panels industry will both be ready markets for wood waste. “What could be better for the timber industry than having its waste collected or, even better, being paid for it,” he said.

Aiming high

Having pointed out timber’s disappointing record on waste, Mr Scott must have been heartened to see a slide presented by final speaker, Andrew Waugh of Waugh Thistleton Architects. He presented his practice’s nine-storey Stadthaus apartment building in London, based on cross-laminated timber panels. He outlined the benefits of using this engineered wood product in terms of carbon storage, the fact that, as a lighter material, it needs less heavyweight foundations, its speed of erection, and reduced waste. And he illustrated the latter by showing a picture of a week’s site waste on the Stadthaus build – a small, neatly swept pile of timber chips and sawdust.

Having successfully pushed the boundaries once, Waugh Thistleton is going more than a step further – 14 storeys further, in fact – with a 25-storey cross-laminated timber building in Enfield.