Rethinking sustainable construction: a future forged in timber

Globally, the building and construction sectors account for almost 40% of energy-related carbon dioxide emissions, stemming from both operational emissions alongside those from the construction process and materials. Despite the heavy environmental footprint of the construction sector, England faces acute housing challenges. It has the lowest number of houses available in the developed world coupled with the highest rate of inadequate housing in Europe. These circumstances have propelled the government to set ambitious housebuilding targets to meet the growing housing demand. However, the solution is not straightforward.

The temptation to demolish existing buildings to make way for new constructions is strong, especially when considering that 10 million households across the UK exist in conditions that are cold, damp, and poorly insulated. Nevertheless, the environmental impact of demolishing 50,000 buildings annually in the UK is profound, with construction sites making up two-thirds of the country’s total waste at 126 million tonnes.

Yet the deadline to cut global emissions in half is only 6 years away. Circular mass timber construction emerges as a key strategy in the reduction of the industry’s global carbon emissions. Enabling both the retrofitting, restoration, and refurbishment of existing structures as well as the rapid construction of new projects from scratch, mass timber offers versatile solutions for sustainable development across two main project categories.

Mass timber in action

Wood, as a construction material, does what other competing materials cannot – it grows back. Unlike concrete or steel, trees sequester carbon dioxide throughout their lifecycle, moreover, mass timber is the only commercially available material with such high load capacity

and durability that it can replace traditional building materials in mid to large scale building projects, offering a dual benefit of reducing atmospheric CO2 while providing a versatile building material. These unique characteristics of wood underscore its value in creating more sustainable urban environments. As we navigate the complex challenges of housing shortages, environmental sustainability, and the urgent need for emissions reduction, the role of mass timber in construction becomes not just advantageous, but essential.

But how does this work in practice? Ripe for a made-to-order ethos, mass timber can be designed to be immediately compatible with Design for Manufacturing and Assembly (DfMA) principles, streamlining construction by reducing costs, complexity, and environmental impact, while facilitating the rapid assembly of buildings from prefabricated parts. From whole schools and multistorey offices to the reuse of existing building stock, mass timber kits utilising prefabrication techniques enable the assembly of entire building floors within a day, with precut elements, such as stairs, roofs, and floors, arriving ready for quick installation – 30% faster than the construction pace of concrete counterparts. Not only does this method minimise labour and logistical costs, but it also enhances safety and quality control with minimal onsite inspection, allowing for year-round construction across climates with little downtime due to weather-related delays.

An illustrative example of this is Dogger Bank Wind Farm, the world’s largest offshore wind farm. Set to provide electricity to over six million homes, the wind farm’s operations and maintenance building is an ultra-low carbon base for 400 workers, also home to the control room, which will provide 5% of the UK’s total electricity. Built using custom made elements from Sylva™️ by Stora Enso CLT Roofs and Floors product range, partnered with B&K Structures, the base also accommodates warehouses for spare parts of the windmills – two and a half times the height of Big Ben, and their equally enormous service operation vessels for transporting the windmills to the North Sea. Built in only 14 months, the use of mass timber kits for accurate, sustainable, and fast-to-install offsite construction shows the potency of using the material for projects with high environmental and efficiency requirements, setting a precedent for future developments.

Preserving the past, protecting the future

The light-weight nature and workability of timber makes it ideal for retrofitting, extending the life of existing buildings that have passed their

intended use and saving the millions of tonnes of waste and pollution that comes from demolishing buildings. For Arding & Hobbs Department Store, retrofitting was the ideal solution to bring the Grade II listed heritage building back to life. With the ground floor opening a pub and restaurant blend in late 2023, the rest of the mixed-use redevelopment is at the cusp of completion, including a biodiverse rooftop

extension, built from Stora Enso’s Sylva Roofs and Floors kit, again partnering with B&K Structures, and CLT framed roof pavilion clad in scalloped brass to heighten the building. New floors rest on existing columns and spine walls, applying a lightweight steel and timber structure that requires only minimal modification within the floors below, while great lengths were taken to ensure care for the existing fabric of the department store, preserving original features such as two ornate, stained glass dome windows in the high ceilings, the clock tower, and baroque architectural details. Here, mass timber creates a way to enhance historic features, whilst also ensuring construction remains architecturally sensitive and environmentally sustainable.

The material of tomorrow

Looking to the future, mass timber is not merely an alternative; it is a pivotal element in the sustainable transformation of our built environment. Industry transformation is already in motion, from the grand scale of projects like Dogger Bank Wind Farm to the revitalisation of historical buildings like Arding & Hobbs Department Store. Here, mass timber’s adoption for efficient, offsite construction and retrofitting alike represents a vital step towards meeting global emissions targets, addressing the building stock crises, and cultivating a deeper connection between natural materials and architectural design, offering a clearing in the forest of climate challenges, and paving the way for a greener, more resilient future.

By Mila Duncheva, Business Development Manager at Stora Enso

Images: Arding & Hobbs image credit: Stora Enso Partner: B&K Structures/©Richard Chivers

Dogger Bank Wind Farm image credit: Stora Enso Partner: B&K Structures

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