Rethinking Timber Buildings

Seven perspectives onthe use of timber in buildingdesign and construction Foresight, Research and Innovation is Arup’s internal think-tank and consultancywhich focuses on the future of the built environment and society at large. We help organisationsunderstand trends, explore new ideas, and radically rethink the future of their businesses.We developed the concept of ‘foresight by design’, which uses innovative design toolsand techniques in order to bring new ideas to life, and to engage all stakeholders in meaningfulconversations about change. For more information on our foresight publications and services,please email foresight@arup.com. To contact our global timber team, please email timber@arup.com. March 2019 13 Fitzroy StreetLondon W1T 4BQarup.comdriversofchange.com© Arup 2019 Contents Foreword4 Preface6 Introduction8 1. Managing our carbon budget14 2. Urban densification24 3. Wood and well-being32 5. Sustainable sourcing54 6. Knowing the material64 7. Innovating with wood74 Conclusion84 References91 Acknowledgements99 Urbanisation and human population growth are increasing thepressure on our planet’s precious resources with visible signsof anthropogenic damage. It is estimated that two billion squaremetres of new building stock are needed every year between 2019and 2025, especially for housing. Global carbon dioxide emissions(CO2) have increased by almost 50% since 1990. The constructionindustry alone produces around 15% of these global emissions. Tim SnelsonAssociate DirectorLondon There is an urgent need to limit global warming to 1.5°C toprevent the worst impacts of climate change, as stated in theIntergovernmental Panel on Climate Change (IPCC) specialreport on climate change released in October 2018. This strategyrequires greenhouse gas emissions to be cut to net zero by around2050. Net zero is the point at which greenhouse gas emissionsare balanced by the removal of these gases from the atmosphere.An intermediate target of 45% reduction by 2030 is alsorecommended. We all need to take responsibility to make changesto energy systems, changes to the way we manage land andchanges to the way we move around with transportation. We alsoneed a radical rethink in our approach to construction to delivera net zero built environment. Above: Metropol Parasol,Seville, Spain. Timber is one of our most traditional construction materials and has a key role to play on bothsides of the net zero balance. Forest enhancement is seen by many governments as a crucialpart of their emissions mitigation strategy, as trees absorb carbon from the atmosphere to grow.Timber is also less carbon intensive to manufacture, transport and erect than steel and concretestructures. Therefore, increasing the use of timber in our buildings will reduce the carbon impactof construction. A thriving sustainable forestry sector also contributes to the non-urban economy,reducing urbanisation. The timber industry has been enjoying significant growth in the last decade, primarily due tothe increase in mass timber products such as cross-laminated timber, glulam and laminatedveneer lumber, as well as many board products such as OSB, that make use of smalleroffcuts. Yet timber as a structural material seems to invoke a more emotive response than itscompetitors, dividing opinions and stifling the much-needed debate on how and where timbercan best be used to safely develop low-carbon buildings; namely by addressing furtherresearch needs in relation to fire safety performance, floor dynamics, robustness and durability. This wide-ranging report explores seven different perspectives on the use of timber in buildingdesign and construction. I hope it informs debate and moves the discourse forward on theincreasing use of timber as part of the construction industry’s concerted endeavour to builda safe, resilient and net zero future. Preface This report is intended for anyone wantinga strategic overview of timber construction andits recent upsurge in popularity. It considersseven perspectives on the use of timber inbuilding design, exploring where and when itis used, factors influencing its adoption, andhow it might evolve. These seven factors bestreflect timber’s current social, technological,environmental, economic and political context,and provide a broad and holistic review: Terminology This report describes a new method ofdesigning and constructing multi-storeytimber buildings, variously calledmassivholz(German), mass timber, massive timber, heavytimber, solid timber, or engineered timber.The term used in this document is masstimber.1The performance characteristics ofmass timber are different to those of traditionalstud and joist construction in just about everyrespect such as structural, fire resistance,building acoustics, physics and dynamics. 1. Managing our carbon budget2. Urban densification3. Wood and well-being4. The future is prefabricated5. Sustainable sourcing6. Knowing the material7. Innovating with wood The re