Professor Robert Hairstans, Director of the Centre for Advanced Timber Technology (CATT) at the New Model Institute for Technology and Engineering (NMITIE) has a deep knowledge and understanding of timber and the offsite sector. How do these fit into the wider requirements of sustainable construction?
Q: Due to be in full operation later this year, can you give a brief outline of the ethos and direction of NMITE & CATT?
Robert Hairstans (RH): As the building is being built, we’ve been busy assembling the team, engaging with partners and stakeholders and importantly evolving the educational system via the Timber Technology Engineering and Design (TED) programme of work which is now at an advanced stage. NMITE, Edinburgh Napier University (ENU) and Timber Development UK (TDUK) are the lead partners with a steering committee that represents the sector including the Structural Timber Association, Trussed Rafter Association, Swedish Wood and an industry working group representative of the supply chain to establish the competency framework via Harlow Consultants.
The Timber TED competency framework has been used to inform the educational webinar series of the UK-wide TDUK student design challenge – running in the first quarter of 2022 on the Southside Hereford 1 project. This is to design a low carbon community building for Growing Local, Belmont Wanderers and NMITE. There are 12 multidisciplinary teams formed for the challenge from across 33 UK universities. These learners will have access to software from project partner organisations which including Trimble, Passive House Planning Software (educational version) and the Alliance of Environmentally Conscious Buildings (AECB) Life Cycle Analysis Software.
Q: The formation of a ‘Living Lab’ within CATT sounds an exciting development – what will it offer and deliver for those seeking a career in timber design?
RH: We want the building itself to be an educational toolkit. A ‘Living Lab’ creates the necessary conditions for research to be undertaken and innovations created and validated collaboratively in multi-contextual, empirical real-world environments – and all enabled by digital approaches. This concept – including connectivity to other partner living lab projects – will include in-situ measurement of thermal, acoustic, and structural performance via thermocouple, accelerometers, strain gauges and other embedded sensors, with feedback loops to digital models for performance evaluation.
We want to engage the sector with the building and determine opportunities for collaboration on the Living Lab approach. We are working with Stora Enso – the cross laminated timber (CLT) supplier of the building – on the application of 48 sensors to collect data with an emphasis on moisture management. We want to dashboard this information and use it for improved understanding for learners and industry professionals including insurance and warranty providers. We have a unique position here where we can use the building as a live experiment and tool for information.
Q: Have we reached ‘peak timber’ in the UK? With timber imports at the mercy of global supply chains and the associated costs and risks – can we genuinely grow more homegrown engineered timber?
RH: According to ONS data, we have around 3.23 million hectares of woodland in the UK covering around 13% of land, and while each year, all timber suitable for harvesting is processed and used for a range of purposes, we remain the secondlargest importer of forestry products, behind only China. The UK currently produces approximately 3.4 million m3 of sawn softwood per annum – 30% of which is used for construction. There is therefore scope to grow more and as well as enhance our current use. This is not to mention the timber that can be reclaimed and upcycled – there is huge potential to do a lot more.
Historically, timber grown in the UK has been used mainly for non-structural applications such as fencing and pallets, as well as repair, maintenance, and improvement activities. But continued research is proving the potential for the use of homegrown, engineered timber to create the fabric and structure of buildings. There are several advantages to using engineered timber over more carbonintensive traditional building materials – for example, buildings are lighter and have a reduced gravitational load, typically weighing 20% less than concrete. For those that want more info I would highly encourage monitoring the outputs of Construction Scotland Innovation Centre led and Innovate UK funded Transforming Timber Project.
Q: Embodied carbon seems to be the new battleground and area of study. How can this be quantified, interpreted easily and thereby reduced across the built environment?
RH: Natural, renewable materials have significantly lower levels of embodied carbon, particularly when compared with materials like steel and concrete. Think of it this way, a 10,000m3 per annum CLT plant, would sequestrate 6,760,000kg of carbon dioxide (CO2) from the atmosphere assuming – 676kg of CO2 per m3 will be stored after the production process. A recent study also estimates 50 Mt greenhouse gases (CO2e) in up-front avoided emissions, without considering any carbon sequestration and storage potential offered, would result from substituting concrete floor slabs with timber in steel building frames for the next 30 years.
The embodied carbon of a house constructed using offsite panelised timber frame (with the majority embodied in the concrete substructure) is approximately half of that using traditional masonry forms. However, whilst recognising the environmental credentials of timber relative to other construction materials, it is necessary to ensure theories of circularity are applied to ensure maximum value return from the resource, and the impact of other associated activities as part of the dynamic process to delivery utilising the five capitals (manufacturing, financial, natural, social, human and natural) model.
Understanding of this is critically important given we spend 80-90% of our time in the built environment and construction is a major contributor to climate change with buildings and construction together accounting for 36% of global final energy use and 39% of energy-related carbon dioxide (CO2) emissions. The utilisation of timber, a naturally renewable carbon sequestering resource, for construction delivery can produce low energy buildings (employing a fabric first approach) efficiently with enhanced levels of productivity and minimum waste.
Q: What core changes in behaviour and specification can architects and structural engineers do to help tackle climate change and provide energy efficient housing?
RH: To reach net zero by 2050 the culture of construction requires to change and become more collaborative. This requires improved levels of human capital that is underpinned by skills. Increasing the use of environmentally sound biogenic and ecological construction materials such as timber, will need to be based on a holistic value proposition and corresponding knowledge sets (productivity, environmental and social impact, cost and building performance over time).
The educational approach of NMITE is to apply a student-centric learning methodology with a curriculum fuelled by real-world challenges, meaning that the approach will be distinctive in the marketplace and will attract a different sort of engineering learner. The mission statement of CATT is to “stimulate collaboration across the industry both vertically (seed to end product) and horizontally (architecture, construction, digitalisation) as a common theme together with showing a wider audience how rewarding a career in timber can be.”
Q: Industry 4.0, digitisation and all the technical wizardry that it entails – how important to offsite construction and attracting new entrants into the sector are these new tools?
RH: Industry 4.0 (the fourth industrial revolution) is digitisation where the Internet of Things (IoT) enables digital connectivity between everyday objects. Over the next decade this level of connectivity will accelerate, with assets becoming increasingly more ‘intelligent’, presenting opportunities for innovation, creativity and transformation in the built environment. Industry 5.0 personalisation is the next step, with the collaboration of human skills and digitisation. Workers in Industry 5.0 will be upskilled to provide value-added tasks in production, leading to mass customisation and personalisation for customers.
The pre-manufacture of construction products can range from component based sub-assemblies manufactured offsite to volumetric systems with high levels of enhancement offering turnkey solutions. Other industrialised options include near to site pop up factories or on-site precision manufacture. These approaches require the utilisation of CAD/CAM combined with CNC machines hence the importance of digitisation and digital skills. These approaches and concept will of course attract new entrants as this is a shift away from the preconceptions of the traditional construction sector and is a move towards a cleaner, safer working environment.
Q: Improving productivity is a concern across the construction sector and the UK generally – how can factory-based manufacture improve that?
RH: The utilisation of timber with factory based and precision engineered approaches offers significant benefits when consider the productivity challenge and levels of on-site waste – construction and demolition waste (CDW) accounts for more than a third of all waste generated in the EU. A Design for Manufacture and Assembly + Disassembly and Reassembly (DfMA+d and R) approach ensures the regulatory lifespan of a building (60 years) is significantly exceeded through the recycling and reuse of structural timber at the end of its standard lifecycle, locking up the carbon for longer. This standardised, mass customisation approach (customising standard components to meet with client requirements) also supports significant flexibility and adaptability when considering the redesign and re-engineering of buildings whilst in use.
The utilisation of timber and biogenic delivery of the built environment has been evidenced to be the most environmentally sound approach when adopting DfMA+d and R approaches (avoiding landfill) given 90% of combustion emissions could potentially be captured using bioenergy with carbon capture and storage (BECCS) at absolute end of life. Modularity of systems also require more upfront design, the utilisation of a standardised approach as well as the utilisation of digital design. All of this lends itself to the above.
Q: Precision-engineered timber such as CLT and modular offsite systems are one of many options available to ‘unlock’ net zero housing – can it deliver more affordable homes as well as private residential newbuild?
RH: Timber should be top of the list for built environment delivery given its environmental credentials and I would therefore argue that that advanced timber technologies available can now respond to the varying needs of the sector from restoration, retrofit to newbuild solutions (domestic, non-domestic including educational, healthcare and industrial buildings) and infrastructure (bridges, electricity transmission towers and wind turbines).
The array of products and systems available is vast from dimensional timber, engineered products, composites and mass timber systems utilising glue, mechanical and moisture movement forms of fixity. Further, relative to end use and durability classification (internal or external environment) or associated risk of fire there are varying forms of treatment including heat modification, acetylation and fire retardants. Digitisation combined with modern manufacturing approaches is unlocking the potential of these products and how they can respond to the given context.
Q: Looking ahead – can offsite construction in all its materials and systems – help deliver better circularity and achieve the complex 2030/2050 net zero targets everyone hopes for?
RH: Yes, if the emphasis is on biogenic offsite construction whereby there is a convergence of the renewable resource (forestry, woody biomass and naturally replenishable) and construction sectors to enabling the sustainable manufacture of the built environment. The approach will require to harness digital technologies and be capable of evolving to meet the needs of future generations without impinging upon available resource whilst offering a better quality of life aligned with the UN’s Sustainable Development Goals.
By increasing the use and value of UK grown resource and establishing more sustainable forestry in the UK a seed to building supply chain will be created stimulating economic growth providing jobs and wealth creation in remote and rural communities, instigate start-ups and secure the longterm success of currently established organisations by enabling scale in the market. This will ensure a resilient UK construction sector that is less reliant on non-renewable resources and correspondingly a major contributor to the climate change.
For more information on the work of CATT and NMITIE visit: www.nmite.ac.uk For more on the Transforming Timber Project – From Forest Floor to Built Environment visit: www.transformingtimber.co.uk
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