Growing acceptance of timber

Timber is seeing a strong resurgence across many construction sectors due to sustainability drivers, but obstacles remain. ADF canvasses industry views.

Each year the UK produces 11 million tonnes of steel, 12 million tonnes of concrete and 11 million tonnes of timber. Most of this is destined for building sites across the UK, having been selected by architects and specifiers.

All three materials are widely used for the structural framework of buildings and all have their strengths. However, when making the choice between different material options, what has not always in the past been considered as part of the decision-making process is the relative environmental credentials of each. As the focus on sustainable building practices becomes increasingly intense, those comparisons are becoming ever more important to the specifiers in the industry.

“Sustainability and environmental consideration have been hot topics in the construction industry for a number of years now,” says Tim Belden, university liaison manager at The Timber Research and Development Association (TRADA). “As an architect, if you’re serious about lowering your impact on the environment and global warming, you should be using timber wherever appropriate; it’s the
obvious choice.”

Although this view has been widely adopted in continental Europe, it has failed to catch on in the UK despite the unambiguous findings regarding the carbon footprint of each material. “One tonne of concrete produces 927 kg of CO2 per tonne of end product – that’s almost a 1:1 ratio,” says Belden.

“If we look at steel, dependent on variety, approximately 1.8 tonnes of carbon dioxide is produced for every tonne of end product. These are huge numbers that have a significant impact on our environment.”

The positives of negative footprint

Timber, on the other hand, has a very different environmental impact. Due to its ability to absorb and store carbon in its fabric, timber consumes more CO2 than is emitted back into the atmosphere during its processing. Belden continues: “Let’s take cross laminated timber (CLT) for example.

For each tonne of product grown, processed, prepared and shipped to site, 300 kg of CO is removed from the air.

Timber production therefore has a negative carbon footprint, meaning we’re not only protecting the environment, we’re helping to improve it.”

This data comes as no surprise to Stuart Devoil, head of marketing and brand at timber panel manufacturer MEDITE SMARTPLY, who explains his company’s approach to sourcing timber: “Made from fast-growing softwoods in our own sustainably managed FSC-certified forests in Ireland, our products actually consist of the by-products from timber production.” He continues: “Our timber panels use material that would otherwise be used as fuel or simply disregarded: wood residues, sawmill co-products and pulpwood. Whatever we don’t deem suitable for product manufacture, we use in the generators to power the processing machinery.”

Cost

It’s not just environmental benefits that timber construction materials add to the material choice mix – the projected cost outlook is also becoming increasingly appealing to specifiers. Belden says, “While the cost of raw materials in steel and concrete can fluctuate, especially in the case of steel, timber costs remain fairly predictable. With the increased interest in building with timber frame we’re forecasting that the price will continue to decrease in the next few years.”

The demand for timber as a construction material has been firmly established with architects and specifiers for many years. However, increased focus on sustainability in the built environment is beginning to turn even more heads. Duncan Baker Brown, director at East Sussex architects BBM Sustainable Design, clarifies: “When we’re working on projects, we want to assess the whole supply chain to understand exactly where our raw materials have come from. The most accessible and eco-friendly product that we can do this with is timber. It’s a material trend that is growing, but we’ve been using timber in our projects for many years due to its environmental credibility and qualities.”

Large-scale uptake

So, if the environmental argument for building with timber stacks up and the cost is on a par with steel and concrete, why aren’t we seeing more people building with it?

“I don’t know. That’s the short answer,” claims Belden.

“I think people still have in their head that timber is trees swaying in the wind.” He adds: “I always ask – what building do you think of when you think timber frame? A lot of the answers make reference to Tudor style buildings. Tudor buildings are a great example of timber frame construction: they’ve been up for 400-500 years. If that’s not durable and sustainable I don’t know what is!” Belden concludes, “There’s not many concrete structures over 50 years old that are still in an inhabitable shape, and I’m sure they don’t have the same charm.”

Demand for timber in construction is growing, and some of the factors for that are the material’s sustainable attributes, negative carbon footprint, and durability. With constant innovation bringing about new products such as flame retardant and airtight variants of timber panel and boards, it seems the uses and demand for this product will only continue to grow.