As the global demand for sustainable construction materials intensifies, secondary timber is emerging as a critical solution for reducing waste, lowering carbon emissions, and achieving circularity in the built environment. This approach centers on repurposing timber that would otherwise be discarded, turning it into engineered products like cross-laminated secondary timber (CLST) and glued-laminated secondary timber (GlulamST). These innovations offer an alternative to conventional timber sourcing and provide a realistic, scalable pathway toward meeting environmental goals.
Why Secondary Timber Matters
In many parts of the world, including the UK, supply limitations in domestic timber harvesting create pressure to find alternative solutions. At the same time, the construction and demolition sector generates a high volume of timber waste. Typically, this material is downcycled into low-grade products, used for energy recovery, or simply ends up in landfills.
Secondary timber offers a higher-value route for this material. Through processing and engineering, waste wood can be transformed into building products suitable for cladding, structural applications, and prefabricated panels. The environmental benefits are significant: using secondary timber eliminates the need for additional tree harvesting, reduces transportation emissions, and keeps valuable material in use for longer periods.
How CLST and GlulamST Work
CLST is modeled after cross-laminated timber (CLT), a product formed by gluing layers of timber at right angles to one another. The key difference is the source of the wood. CLST is made from reclaimed or salvaged wood that has been cleaned, cut, and reassembled to meet modern construction standards. GlulamST follows a similar model but focuses on linear elements bonded together in parallel rather than in layers.
These products are tailored to meet design and performance requirements similar to their conventional counterparts. With modular sizing and disassemblable construction, they are well suited for smaller-scale, adaptable architecture. Their production also allows designers to highlight the story of the material, giving new life to wood that may be hundreds of years old.
The Supply Challenge
Scaling the use of secondary timber depends heavily on logistics and infrastructure. Unlike primary timber, which comes from managed forests, reclaimed timber is scattered across demolition sites, industrial buildings, and other sources. Gathering, sorting, cleaning, and reprocessing the material into standardized sections is labor-intensive and currently lacks widespread systems for efficient collection and distribution.
Still, with rising interest from architects, developers, and housing associations, the demand for locally sourced and low-impact materials is growing. Compact, mobile manufacturing hubs—such as micro-factories deployed near urban redevelopment areas—are being considered as one way to overcome these challenges. Such decentralized systems could make localized CLST production more feasible and cost-effective.
Benefits of Secondary Timber
- Reduced Carbon Footprint: No additional tree harvesting or long-distance shipping is needed.
- Waste Reduction: Diverts usable wood from landfills and low-value applications.
- Material Transparency: Known origins and shorter supply chains support ethical sourcing.
- Circular Economy Integration: Designed for reuse and adaptability over multiple lifecycles.
- Unique Aesthetics: Aged wood often has character-rich textures and histories.
What’s Holding It Back?
The expansion of secondary timber use in structural applications is slowed by several factors, including a lack of standardization and insurance-related hesitations. Without formal grading standards for reclaimed timber’s structural properties, engineers must take additional steps to confirm safety and reliability. These steps add time and cost, creating friction for widespread adoption.
However, progress is being made. Organizations and researchers are working to develop strength-grading techniques and adapt existing codes to support secondary timber’s use. Meanwhile, early projects like demonstration pavilions and modular structures are building awareness and showcasing real-world feasibility.
Cost Considerations
Currently, secondary timber is not always cost-competitive with mass-produced primary CLT from large European manufacturers. The difference in scale and automation contributes to price differences. However, this gap may shrink as policies evolve. For example, future regulations around embodied carbon, waste minimization, and product traceability could give a pricing edge to reclaimed materials.
Some builders and designers are already willing to pay more for sustainable and story-rich materials. In particular, when reclaimed timber comes from historically significant or aged sources, the uniqueness of the product adds aesthetic and cultural value that standard materials cannot replicate.
Where Secondary Timber Is Headed
Interest in secondary timber is no longer confined to academic research or niche architecture. It’s becoming a practical consideration in a variety of sectors—from social housing and small commercial projects to high-profile design showcases. As logistics improve, CLST and GlulamST may become integral components of green building strategies across Europe and beyond.
What Makes Secondary Timber Different?
Unlike virgin lumber products, secondary timber carries a story. It comes from buildings that may be centuries old and has the potential to last for hundreds of years more. The approach avoids the environmental cost of logging, shipping, and waste, while offering durable, versatile alternatives to new wood. Its applications are expanding—from cladding and joinery to modular structural systems—and it aligns perfectly with goals for local sourcing and carbon reduction. As policies shift toward circularity, its relevance is only expected to grow.
A Future Built on the Past
In five years, secondary timber could become a mainstream option for circular construction in urban environments. Movable production units, strong local sourcing networks, and evolving grading systems will help accelerate adoption. Beyond the technical and economic aspects, there’s a cultural shift underway: toward valuing materials not just for performance but for provenance and story.
Secondary timber embodies that shift. As governments and industries push for net-zero buildings and waste-free supply chains, products like CLST and GlulamST will help close the loop. With proper investment, policy alignment, and ongoing innovation, this wood from the past could form the backbone of the future.
Woodn’t You Like to Use It?
Secondary timber is more than just a recycled material—it’s a smart, sustainable choice with architectural flair and environmental credentials. Whether you’re a developer seeking low-carbon solutions or a designer looking for meaningful materials, this is one movement that’s worth joining before it goes mainstream.