Future of construction is hybrid and circular – rethinking the use of materials

Limited natural resources, biodiversity loss and climate change are urging societies to move toward sustainable solutions (1) and construction industry is not an exception to the changes and shifts in global industry trends.

Buildings are responsible for about 40% of the EU’s total energy consumption, and for 36% of its greenhouse gas emissions from energy. The embodied carbon in construction is estimated to account for about 10% of total yearly greenhouse gas emissions worldwide (2). A key ingredient in the challenge is re-thinking how different materials work together.

Hybrid construction looks at different materials and their properties and possibilities in an innovative way to complement each other. It is not a black and white issue between materials, but a fresh way to look at how materials complement each other and perform  at their strongest. The materials come together to optimize structural performance, as the concrete resists compression while the wood with its capacity to flex, offers tensile strength. There are two ways for hybrid construction; combining building elements, or combining building materials within an element. Both ways have one thing in common; material efficiency and reusing elements when possible are at the core of hybrid construction.

Best solutions combine different materials and their strengths

When combining elements in hybrid construction, wood products can be used alongside other materials, for example, by prefabricating wooden elements for floors, roofs and walls that are attached to a steel or concrete frame. As timber building weighs less than a concrete building (3), using wood in construction means that building foundations may be built with less concrete. Building D(emountable) in the Netherlands is a great example of hybrid construction that combines a steel frame with wooden Kerto® LVL elements.

Another great example is The Black and White Building office space in London, designed by Waugh Thistleton Architects. The structure of the building is made from laminated veneer lumber (LVL). The reason behind the decision of using LVL is that it is one of the strongest, wood-based construction materials relative to its density. That allows a smaller cross-section for beams and columns than standard softwood. It also maintains a high-quality surface finish from a raw material sourced from sustainable, managed forests.

A step toward hybrid construction can also start with using hybrid elements that combine wood with other materials. The sandwich wall element, created by Metsä Wood and its partners combines concrete façade, insulation layer and Kerto LVL Q-panel as a load-bearing core. Using Kerto LVL makes the elements light to transport and creates carbon storage into the building, making hybrid sandwich wall elements environmentally smart choice. The first construction project to use this kind of hybrid elements is Metsä Fibre’s Rauma sawmill, Finland.

In another example hybrid elements are used for high-quality floors and partition ceilings. Engineered timber takes care of the tensile forces that occur in the structure’s lower part of the cross-section, and the concrete absorbs the compressive forces on the top. The material bridges large spans with improved vibration behaviour and good sound insulation values.

 

 

 

Future with less material use

Material scarcity has been topping headlines, and it is estimated that in the future humanity can face shortage of many raw materials, and the future is said to have less and less components (4). For example sand, an important part of concrete, is a commodity facing a shortage (5). While this may seem a bit distant, it also means that in the future it is even more important to use knowledge and combine components in an innovative hybrid model that allows flexibility between materials and ensures we don’t run out of supplies.  

The most sustainable solutions would be to not build at all or transform old buildings into new use, as Aalto University professor Matti Kuittinen has stated (6). As urbanisation tends to accelerate, the need for construction increases especially in the metropolitan areas. Wood, is a low-emission construction material that allows us to meet the increasing demand for construction, and that’s why it is crucial to use wood for the parts of the building for which wood is best suited.

Re-engineering the way we think

Aside from embracing the latest material innovations and technology, we also need to re-engineer business models and ways to collaborate. Michael Ghyoot from design firm Rotor has stated that we have to find a way to create prosperity and added value from maintenance and management of existing goods, and that requires cooperation between all parties. Increasing the use of wood in construction makes the buildings more environmentally friendly, creating interesting opportunities for investors to be part of the leading edge of the paradigm shift. Already some leading industry players are encouraging companies to commit to sustainable (7) supply chains and are steering their investments toward those public companies that do.

The future of construction industry requires more and more visionary thinking and technical understanding to make wood products to be seen as the efficient material that they already are, and to find the new possibilities and connections between players and materials. By rethinking the way we design our whole  built environment, using new technologies and innovative hybrid construction models, we can drive a systemic change towards a more circular and sustainable society.

References

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    Sources of articles

    (1) https://reader.elsevier.com/reader/sd/pii/S0921344921001622?token=A8A87497DE1011181787F43D5D19ADD6D7746859077ED4B69939015B794
    (2) IRP, Resource Efficiency and Climate Change, 2020, and UN Environment Emissions Gap Report 2019.) https://eur-lex.europa.eu/resource.html?uri=cellar:0638aa1d-0f02-11eb-bc07-01aa75ed71a1.0003.02/DOC_1&format=PDF
    (3) https://www.bbc.com/future/article/20190717-climate-change-wooden-architecture-concrete-global-warming
    (4) https://impact.economist.com/sustainability/circular-economies/enabling-innovation-the-future-of-materials
    (5) https://www.cnbc.com/2021/03/05/sand-shortage-the-world-is-running-out-of-a-crucial-commodity.html
    (6) https://aaltouniversity.shorthandstories.com/ihanteet-uusiksi/
    (7) https://www.bcg.com/publications/2020/the-staggering-value-of-forests-and-how-to-save-them
    Additional:
    https://www.sitra.fi/en/cases/re-using-locally-excavated-earth-to-make-environmentally-friendly-building-materials/
    https://circulareconomy.europa.eu/platform/en/news-and-events/all-events/what-role-do-secondary-materials-play-new-constructions-and-buildings-renovation