In recent years, timber has become a hugely important resource for the Scottish economy. According to a recent report from Scottish Forestry, forestry’s economic contribution to Scotland is now £1.1 billion GVA (Gross Value Added), £878 million of which comes from timber processing and supply chain activities.
In total, Scottish Forestry contributes 76% of the UK’s total commercial forestry market. The sector also currently employs over 34,100 people full-time. This clearly demonstrates that Scotland’s timber is in strong demand. But what are the key reasons for this?
Why is wood replacing other materials?
The demand for timber is being driven by a range of factors, but perhaps the main driver is its sustainability credentials. Wood is a renewable resource that, when sourced from sustainably managed forests with FSC and PEFC certification, has a lower environmental impact compared to traditional building materials like concrete and steel. Additionally trees absorb carbon dioxide as they grow, and much of this carbon remains stored in the wood even after it is harvested and used in construction. Thus, wooden buildings can act as carbon sinks, helping to mitigate climate change.
The aesthetic and biophilic benefits of wood are also key factors. The material appeals to architects, developers and occupants, due to its ability to provide a warmer, more natural environment that can enhance well-being and productivity, making it a popular choice in residential and commercial buildings alike.
Timber’s longevity
The durability of wood has historically been a concern, especially regarding issues like rot, pests, and moisture. However, modern treatments and construction techniques have significantly enhanced wood’s durability. Pressure treatments with preservatives and thermal treatments can protect wood from termites and decay, extending its lifespan substantially.
Additionally, proper design and construction practices, such as ensuring adequate ventilation and moisture barriers, can prevent many common problems associated with wood. Consider that there are constructions with wood that are over 1,200-years-old like some of the temples in the Horyu-ji region in Japan. Admittedly this is largely due to the build quality and the maintenance of the wood. Nonetheless, it does demonstrate what timber is capable of.
Innovative finishes and coatings also play a role in protecting wooden structures from environmental elements, ensuring that they remain robust and aesthetically pleasing over time. Furthermore, ongoing research into genetically modified trees and sustainable forestry practices continues to improve the quality and resilience of timber even further.
The combustibility myth
Despite being one of the world’s oldest building materials, there are still misconceptions about timber’s properties. The largest of these is attitudes towards its combustibility credentials. Although wood is a combustible resource, modern advancements have significantly improved its fire resistance.
Mass timber, also known as cross-laminated timber (CLT), is made by layering and compressing wood, resulting in structures that are both robust and fire-resistant. In a fire, mass timber forms a charred outer layer, which acts as a shield, slowing down further burning. This charring effect helps maintain the structural integrity of mass timber for longer periods, providing essential time for evacuation and firefighting.
Numerous studies (such as Wood & Fire Safety and Fire design of CLT in Europe) have shown that timber can offer equal and in some cases better and longer structural integrity than steel or concrete at high temperatures.
Technological evolution in the timber trade
The timber industry has seen significant advancements, particularly with the development of engineered wood products such as cross-laminated timber, glue-laminated timber (glulam) and thermally modified timber. These products enhance the structural capabilities of wood, making it suitable for a wider range of applications, including high-rise buildings. CLT and glulam are not only strong and durable but also offer design flexibility, allowing architects to create innovative and sustainable designs.
Thermo-wood modifies the molecular structure of softwood types for it to become a lot more durable (and sustainable) and enables it to replace hardwoods that take longer to grow.
Digital technology is also transforming the timber trade like it has done in so many other industries. According to a report by PwC, advanced digital marketplaces and platforms are enabling businesses all over the world to benefit from capabilities that would otherwise not be possible. This is also true in the case of how materials are bought and sold in construction, while digitally designing and modelling wooden structures ensures precision and efficiency in application.
Prefabrication methods are becoming more common, where components are manufactured off-site in controlled environments and then assembled on-site. This reduces construction time, waste, and costs, further driving the adoption of wood in the construction industry.
Ultimately, wood as a construction material offers numerous benefits, from environmental sustainability to innovative design possibilities. Modern engineering has addressed many of the traditional concerns related to wood, making it a viable and attractive option for contemporary construction projects. As technology continues to evolve and the demand for sustainable building materials grows, wood is set to play an increasingly important role in the future of construction.
By leveraging the natural strengths of wood and enhancing them with modern techniques, the construction industry can build greener, more resilient, and aesthetically pleasing structures that stand the test of time.