MIKE JEFFREE (MJ): STORA ENSO HAS A HISTORIC REPUTATION AS A TIMBER AND FOREST PRODUCTS SUPPLIER. TO WHAT EXTENT DOES IT NOW SEE ITSELF ALSO AS A TIMBER-BASED BUILDINGS SYSTEMS, COMPONENTS AND TOOLS PROVIDER?
Dr Mila Duncheva (MD): Stora Enso is a large corporation with a wide range of renewable solutions that encompasses everything from packaging to biomaterials. And, as you say, we are one of the largest forest owners globally, which sits at the centre of our business. Here we’re talking about our Wood Products division – Europe’s largest sawn timber supplier and specifically the team I sit in, which is Building Solutions, where we are the world’s largest CLT manufacturer in the built environment.”
We’ve been making CLT since 2008 so we have long been a leading provider of wood construction solutions and a pioneer of the associated technological development.
We’re constantly innovating, and our Sylva by Stora Enso kit of parts – a range of prefabricated wood-based products for low carbon buildings – are continuously changing to meet the needs of customers, whether that’s developers, investors, or architects. We are always developing additional offerings customers can plug-in alongside the kits themselves, whether that is protective coatings or on-site installation apps, like Sylva360.
MJ: HAS STORA ENSO CALCULATED THE CARBON BENEFITS OF YOUR SYLVA KITS VS CONVENTIONAL CONSTRUCTION IN CONCRETE AND STEEL?
MD: Our Sylva kit of parts can be applied flexibly in nearly every building type including residential, offices, schools, and even large-scale industrial buildings with up to 36m clear spans.
When we analysed the whole life carbon impact* in a study for a typical mixed-use development, we found a traditional concrete frame was responsible for 8.68kg of CO2-e/ m2 per year, whereas a mass timber option can bring that figure to 3.14kg of CO2-e/m2 per year, enabling a significant reduction in emissions. That’s 64% less, including credits from substitution, biogenic carbon storage and carbonation.
MJ: DO YOU SEE THE FUTURE TREND AS BEING TOWARDS EVEN BIGGER AND HIGHER TIMBER-BASED BUILDINGS?
MD: The race to the top is somewhat slowing. I’m now seeing more interest in landscrapers rather than skyscrapers. One of the best examples is the Nanyang Technological University’s Gaia in Singapore, which is an enormous 42,000m2, and would be the second tallest building in the world if stacked vertically rather than horizontally.
The trend right now is less about developing bigger buildings with more timber in them and more about using less timber per square metre of floor area, generating efficiency savings through material optimisation. We are aiming to help our customers stretch that capacity with our Sylva CLT Rib Panels for example, which can reduce the volume of timber needed to build the same floor area by 40% compared to a Sylva CLT floor slab.
MJ: IN TERMS OF RETROFITTING OF EXISTING BUILDINGS USING TIMBER CONSTRUCTION MATERIALS AND SYSTEMS, ARE YOU LOOKING AT USING TIMBER TO ADD EXTRA STOREYS TO RESIDENTIAL AND COMMERCIAL BUILDINGS – USING SO-CALLED BUILDING AIR SPACE?
MD: An important part of the circular economy is preserving the value of materials already within the built environment, so adding to existing buildings is a good way to achieve that longevity of value. This is especially advantageous in high-density places such as London, where we have supplied vertical extension projects since at least 2016, and where the momentum is now growing. Such rooftop builds show-off mass timber’s superb strength-to-weight properties, leading also to being able to use smaller mobile cranes and install straight from the back of the lorry in logistically constrained areas.
To me, the sustainability benefits are closely connected with logistics. We publish independently verified Environmental Product Declarations (EPD) on our website detailing the environmental impact of our products. In Life Cycle Stages A1 to A3 (for us that’s forestry, harvesting, sawmilling and manufacturing) we use a lot of our original data, as we know exactly how much energy was used by which of our mills in which year and what the energy source was. This makes the data more precise than using industryaveraged databases.
By simplifying our logistics and locating our four CLT mills and LVL mill alongside sawmills, we reduce transport emissions between manufacturing steps. Such incremental gains add-up to us emitting 48% less than the industry average CLT manufacturer operating in the UK market.
MJ: HOW IMPORTANT A PART OF THE BUSINESS DOES STORA ENSO SEE SYLVA KITS AND IN WHICH MARKETS DO YOU SEE THEM MAKING GREATEST INROADS?
MD: The Sylva kits are a smaller part of the Wood Products division turnover, but they are a strategic growth area. We are seeing mass timber, also known as engineered timber, growing rapidly internationally because it unlocks use of wood as a sustainable material in applications with higher engineering requirements compared to classic sawn timber. For example, single-family homes are often built using classic sawn timber, as homes tend to have smaller rooms and on fewer floor levels. But for multi-storey offices with heavy equipment on each floor, or largeclear- span sports halls within schools for example, engineered timber products like CLT and LVL can unlock the applicability of wood where otherwise non-renewable materials would have needed to be used.
MJ: STORA ENSO HIGHLIGHTED THE SCHOOL IN BOURDONNIÈRE IN FRANCE AS THE FIRST SYLVA PROJECT TO USE ENGINEERED WOOD PROCESSED ON YOUR AUTOMATED COATING LINE. HOW SIGNIFICANT IS THE LATTER SEEN IN TERMS OF FURTHER DRIVING UPTAKE OF ENGINEERED WOOD?
MD: The automated coating line makes use of highly technologically advanced robotic arms and is a critical way to mitigate against risks such as moisture and it offers reassurance to customers that we maintain a very high level of quality control. Those qualities are especially important in markets where insurance is a critical factor, including the UK.
It’s also important to stress that it isn’t just the technology that brings about benefits, but the associated expertise in our research team. Our customers know they can draw on the knowledge of a specialist who is wholly focused on moisture and always carrying out studies to continuously improve performance of the materials for the whole industry. And our in-house expert team have summarised their knowledge online.
MJ: WHAT OTHER INTERESTING BUILDING PROJECTS IS STORA ENSO CURRENTLY INVOLVED WITH IN THE UK AND THE REST OF EUROPE?
MD: In the UK, the Arding & Hobbs retrofit with B&K Structures leaps to the top of my mind. When faced with the challenge of extending London’s iconic Arding & Hobbs department store without the need for the much less sustainable demolitions, B&K Structures made use of the sustainable prefabricated Sylva CLT kit to add a new top floor to the 1908 heritage building. That helped ensure the structure remained usable, safe and sustainable for future communities to enjoy. It is an excellent example of how we can extend the lives of buildings in an efficient and sustainable manner with mass timber.
If we were to head south to Paris you can find the HOSTA suspended over six lanes of traffic on the Porte Brancion, which we worked on to transform from a wasted space above a busy ring road into a vibrant boulevard. Our partners for this project, Woodeum, France’s low-carbon real estate specialists, leveraged mass timber’s high strength-to-weight ratio to create a mechanical living bridge for Hardel Le Bihan’s architectural design of a seven-storey residence. This is a perfect demonstration of the strength to weight advantages of mass timber. Because of the nature of the structure, concrete would have limited the building to four floors, unnecessarily locking out the three extra floors we could achieve. When it came to the installation process itself, proper planning and efficiently packaged materials meant there was no demand for onsite storage, which would have been difficult to find in a busy urban environment.
Breaking boundaries relies on continuous innovation with materials and thinking from customer’s specific construction requirements to design tailored solutions.
MJ: HOW IMPORTANT WILL GOVERNMENT ENVIRONMENTAL REGULATION AND STRATEGIES SUCH AS THE EU’S GREEN DEAL AND THE UK CLIMATE ACT BE IN DRIVING USE OF TIMBER IN CONSTRUCTION – AND WHERE DOES STORA ENSO SEE TIMBER BUILDING AND THE COMPANY’S ROLE WITHIN IT BEING IN FIVE OR EVEN 10 YEARS’ TIME?
MD: It’s difficult to predict what is going to happen in the very short term, but what we do know is the imperative to achieve net zero, which most companies and countries are working to achieve by 2050.
When it comes to government strategies, the Republic of Ireland is taking a particularly proactive approach, having set up a crossdepartmental timber in construction working group, knowing that they have a great deal of demand on their housing market, and seeing the opportunity of prefabricated timber as a future-facing and sustainable solution to those needs.
We also know mass timber is a major and growing solution to help meet that target for the high emitting construction sector. We’ve been playing our part in supporting those efforts by supplying mass timber to over 20,000 projects worldwide, with many more to come.
