Urban expansion, population growth, and resource constraints question the established and conventional delivery of structural systems and the design and construction of our built environments. Indeed, what can sustainable cities look like? Rapidly growing urban centers are putting immense pressure on having an answer to this question. The answer will evolve, but it might be right under our noses right now!
Our ability to address emerging space and resource constraints and action climate change mitigation in a resilient and sustainable way will be tested. This has become a catalyst for new solutions and innovations in delivering projects. It has also sparked a resurgence in research and the popularity of one of our oldest and most reliable building materials: wood.
Mass Timber projects or heavy timber projects have proven to stack up to traditional construction methods in the building sector (Look outside: steel and concrete buildings are everywhere!) across all factors: cost, productivity, buildability, functionality, and reliability.
With a move towards engineered timber design and mass timber products, the industry can:
- Promote more lightweight, carbon-neutral, and natural resources in the construction
- Provide a unique alternative to commercial and built environments
- Reduce energy consumption and CO2 emissions
- Create healthier living and working spaces - all central tenets of the UN’s Sustainable Development Goals (SDGs).
Mass timber is getting mass appeal
By and large, mass timber is here and here to stay, for now at least. Why? Well, it is a tenable alternative to conventional construction and building types. It is also making impressive headway across the whole construction industry ecosystem and genuinely impacts the competitive marketplace. Simply put, engineered wood products can encompass a wide array of building members and elements from typically low-value but fast-growing softwood trees and turn them into building materials that can rival concrete and steel in strength, durability, and commercial outcomes. All this whilst being a carbon-cutting alternative gives mass timber its appeal.
Recent changes to Australia’s National Construction Code (NCC) have streamlined approvals for up to 8 stories for mass timber structures. There has also been a significant market expansion for locally and internationally sourced and produced mass timber products to deliver and support evolving construction types within the Australian market.
Currently, the most common types of heavy timber in use are:
- Glue laminated timber (Glulam)
- Laminated veneer lumber (LVL)
- Cross-laminated timber (CLT): CLT currently shows the most promise for large-scale construction projects. View some examples here!
As international building codes evolve in a space that hopes to build taller but more sustainable, we will see timber-frame structures, design, and construction follow suit. We expect national building codes worldwide to drive this trend in 2023 and beyond.
The carbon clock is ticking
Possibly the biggest draw of mass timber is its green credentials. As governments eventually transition to regulating carbon and supporting CO2 abatement, businesses will follow suit (conversely, companies could put pressure on the government) and be empowered and incentivized to move toward a clean energy future. This would propel the building sector to research and develop more sustainable construction materials. Currently, the environmental impact of construction is unsustainable. Cement and steel production is high energy and fossil fuel-intensive, with 7% of global CO2 emissions originating from the steel industry alone and cement production accounting for 8% of total global CO2 emissions.
Furthermore, unlike wood, cement cannot be reused or salvaged. While steel can be multi-cycled, it still requires high-temperature processing. Unlike concrete, steel cannot always be manufactured locally; it is typically transported over significant distances, further contributing to carbon emissions.
The resources we extract and the materials we manufacture for different building types contribute enormously to greenhouse gas emissions. Whilst initiatives have been undertaken in these industries to improve energy efficiency, difficulties in transitioning towards a lower carbon footprint have hindered wood construction and mass timber projects. One can argue that end-of-life disposal of wood products and the need to source timbers cut from forests may not be the most appealing third alternative. However, now, timber is one of the only renewable construction materials used today. By its very nature, timber sequesters and removes CO2 from the atmosphere, reducing carbon emissions significantly before and even during construction.
The future can be prefabricated
Adding to its clean record, mass timber construction is a speedy build. Prefabricated and modular construction are popular design methods in the construction sector. Prefabricated buildings comprise components and elements manufactured in remote factories, transported on-site, and assembled into buildings. Studies have already shown that productivity will substantially increase by increasing the proportion of prefabricated elements in a construction project. This will result in faster construction, less waste, noise, disruption, and lower unit and operational costs.
Prefabricated timber frames
There are many benefits to prefabricated mass timbers as well. Prefabricated cross-laminated timbers offer higher dimensional stability and structural integrity than traditional timber-framed systems. Further, the fact that wood is such a lightweight, versatile, and flexible material means that factory handling, transportation, and assembly of elements are substantially more straightforward. While direct cost comparisons still have concrete buildings at an advantage over wood buildings, prefabricated timber’s lightweight nature and the opportunity to speed up construction time and optimize erection programs shift the cost balance.
We can expect significant workforce upskilling in the mass timber construction market to deliver on the promise of significantly shorter construction programs (up to 20-50%) and cut schedules due to advances in modular construction types and prefabrication.
In with the old: let’s innovate!
Interest is growing in building tall and pushing the limits of innovation with structural timber. However, timber in construction is far from a new technique, so is a throwback worth it? Well, it turns out it can be. Research and advances in material science are looking at wood modifications to address timber’s dimensional stability, durability, fire resistance, longevity, and UV sensitivity. The aim is to open up new ways of making timber’s structural performance even more optimized, workable, safe, and sustainable. Fracture mechanics, clear-coating processes, prestressed timbers, timber hybrids, and composites are all spaces we watch keenly.
The construction sector as a whole is at the precipice of significant innovations that are mainly in the form of new design tools such as Building Information Modelling (BIM), 3D rendering software, Augmented Reality (AR), Design for Manufacturing and Assembly (DfMA) and data integration technologies. These innovations themselves further expand the possibilities for mass timber construction and design. These tools aim to find solutions to common and emerging constraints within the construction sector, making room for efficiency, productivity, reliability, safety, and sustainability advances. They open the door for designers and engineers to address problems in a more integrated way. These emerging and sophisticated approaches could boost its market share and consolidate the fact that timber is indeed well-suited to these new business models.
Wood and wellbeing: time to ‘spruce’ up our living and working spaces.
Humans have used wood as a building material for millennia. Trees are essential in promoting biodiversity, reducing the heat island effect and noise, and cleaning surrounding air and water, even in urban settings. Yet the role of wood as a factor in better health and well-being in both external and internal environments has been anecdotal for a long time. Only now are wood’s biophilic benefits being seriously researched and understood.
Inside our homes, work, or public spaces, access to natural materials like wood has led to decreased occupant stress, greater confidence, and better social integration. A study commissioned by Forest and Wood Products Australia, focusing on the impact of wood in the workplace and on people, found a correlation between employees’ physical, mental, and emotional health and the presence of wood. Benefits included overall worker satisfaction, lower absenteeism, and enhanced productivity. Evidence-based research is making strides in quantifying how people’s access to nature inside and around the workplace or the home contributes to measurable social and economic benefits.
So, what does this change? Well, quite a lot. Quantifying how our built environment can improve productivity, efficiency, and overall quality of life would significantly impact the building sector and design and construction priorities. Currently, building rating schemes such as WELLs incentivize building designs to promote physical and emotional occupant health. Following that, architects and designers will be encouraged to make holistic decisions based on biophilic design and material choices, which then reverberate in engineering design.