Timber Construction and BREEAM Certification: A Symbiotic Relationship for Sustainable Building Practices

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

Abstract

This research report explores the integral role of timber in achieving Building Research Establishment Environmental Assessment Method (BREEAM) certification, a globally recognized standard for evaluating the environmental performance of buildings. The report investigates the symbiotic relationship between the inherent sustainable qualities of timber and the credit criteria within BREEAM, highlighting how strategic timber use can significantly contribute to a project’s overall BREEAM score. It examines the specific BREEAM categories where timber construction offers distinct advantages, including materials, energy, and health & wellbeing. Furthermore, the report critically analyzes the challenges and opportunities associated with maximizing timber’s potential within the BREEAM framework, addressing issues such as sustainable sourcing verification, life cycle assessment considerations, and the impact of building regulations. The research emphasizes the importance of a holistic approach to timber specification, encompassing material selection, design strategies, and construction practices, to optimize both environmental performance and BREEAM compliance. Finally, the report looks at future trends and innovations in timber technology and their impact on meeting increasingly stringent sustainability targets within the built environment, particularly concerning embodied carbon and circular economy principles.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

1. Introduction

Sustainability has emerged as a central tenet in modern construction, driving the adoption of green building rating systems like BREEAM. These systems provide a framework for assessing and mitigating the environmental impacts of buildings throughout their lifecycle. Timber, as a renewable and potentially carbon-negative material, holds a prominent position in this paradigm. This report delves into the intersection of timber construction and BREEAM certification, investigating how timber’s inherent properties and strategic application can significantly enhance a building’s environmental performance and contribute to achieving higher BREEAM ratings. The research goes beyond a simple enumeration of benefits, critically assessing the practicalities, challenges, and future possibilities of utilizing timber to its full potential within the BREEAM framework.

While BREEAM does not mandate the use of timber, its framework inherently favors materials with low environmental impact, renewable sourcing, and positive lifecycle characteristics – all qualities strongly associated with responsibly sourced timber. This report seeks to provide a comprehensive understanding of how these qualities translate into tangible BREEAM credits and contribute to a building’s overall sustainability profile.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

2. Timber’s Sustainable Attributes and BREEAM Categories

Timber offers a range of sustainable attributes that align directly with BREEAM’s assessment criteria. These attributes can be broadly categorized into:

• Renewability: Timber is a renewable resource, unlike many conventional construction materials. Sustainably managed forests ensure continuous regeneration, minimizing depletion of natural resources.
• Carbon Sequestration: Trees absorb carbon dioxide from the atmosphere during their growth, effectively storing it within their wood. Utilizing timber in construction effectively locks this carbon away for the lifespan of the building, contributing to carbon mitigation.
• Low Embodied Energy: The energy required to process timber is generally lower than that required for manufacturing materials like concrete, steel, and aluminum, resulting in a lower carbon footprint.
• Biodegradability: At the end of its lifespan, timber can be safely disposed of or reused, reducing waste and promoting circular economy principles.

These attributes are directly relevant to several key BREEAM categories:

• Materials (Mat): This category assesses the environmental impact of construction materials, focusing on their embodied energy, resource depletion, and pollution potential. Using timber from responsibly managed forests can contribute significantly to achieving credits in this category. BREEAM awards credits for using materials with Environmental Product Declarations (EPDs) and for materials sourced responsibly, as verified by certifications such as FSC (Forest Stewardship Council) or PEFC (Programme for the Endorsement of Forest Certification).
• Energy (Ene): While timber itself doesn’t directly generate energy, its use can indirectly reduce energy consumption. For instance, timber frame construction can offer superior thermal performance compared to concrete or steel, reducing the need for heating and cooling. This, in turn, can contribute to credits in the Energy category. Furthermore, the lower embodied energy of timber compared to other materials translates into a reduction in the overall carbon footprint of the building, which is increasingly considered in energy-related assessments.
• Health & Wellbeing (Hea): Timber has been shown to have positive effects on indoor air quality and occupant wellbeing. Its natural hygroscopic properties help regulate humidity levels, reducing the risk of mold growth and improving indoor comfort. The aesthetic appeal and biophilic qualities of timber can also contribute to a more pleasant and productive indoor environment. These factors can contribute to credits related to indoor environmental quality and occupant comfort within the Health & Wellbeing category.
• Waste (Wst): Utilizing timber in construction can minimize waste generation due to its versatility and ease of modification. Off-site fabrication and prefabrication techniques, commonly used with timber construction, can further reduce waste on-site. Additionally, timber waste can be readily recycled or reused, promoting circular economy principles and contributing to credits in the Waste category.

It is critical to note that the impact of timber on BREEAM scores depends heavily on its responsible sourcing. Using timber from illegally logged or unsustainable sources can negate its environmental benefits and even negatively impact a project’s BREEAM rating. Verifiable chain-of-custody certification, such as FSC or PEFC, is essential to demonstrate compliance with BREEAM’s responsible sourcing requirements.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

3. Challenges and Opportunities in Maximizing Timber’s BREEAM Potential

While timber offers significant advantages for BREEAM certification, several challenges and opportunities need to be addressed to fully realize its potential:

• Sustainable Sourcing Verification: Ensuring that timber is sourced from responsibly managed forests is paramount. BREEAM requires verifiable chain-of-custody certification, but the cost and complexity of obtaining and maintaining these certifications can be a barrier for some suppliers and contractors. Furthermore, the interpretation and enforcement of sustainable sourcing requirements can vary across different BREEAM schemes and geographies. Developing standardized and streamlined certification processes is crucial to facilitating wider adoption of sustainable timber practices.

• Life Cycle Assessment (LCA) Considerations: While timber generally has lower embodied energy than other materials, a comprehensive LCA is necessary to accurately assess its environmental impact. This assessment should consider the entire lifecycle of the timber, from forest management and harvesting to transportation, processing, construction, and end-of-life disposal or reuse. Factors such as the distance timber is transported and the energy source used for processing can significantly affect its overall carbon footprint. The development of standardized LCA methodologies for timber construction is essential to ensure accurate and consistent environmental assessments.

• Building Regulations and Fire Safety: Building regulations often present challenges for timber construction, particularly regarding fire safety. While timber is inherently combustible, engineered timber products like CLT (Cross-Laminated Timber) and glulam (Glued Laminated Timber) offer excellent fire resistance due to their charring properties. However, demonstrating compliance with fire safety regulations can require extensive testing and engineering analysis. Harmonizing building regulations to recognize the fire-resistant properties of engineered timber and promoting performance-based design approaches are crucial to facilitating wider adoption of timber construction in high-rise buildings and other applications.

• Durability and Maintenance: The durability and maintenance requirements of timber structures are often perceived as a concern, particularly in exposed environments. However, with proper design, detailing, and preservative treatments, timber structures can achieve long lifespans comparable to those of concrete or steel structures. Educating architects, engineers, and contractors on best practices for timber design and construction is essential to ensure the longevity and durability of timber buildings. Regular inspections and maintenance are also crucial to prevent deterioration and extend the lifespan of timber structures.

• Skills Gap and Training: The increasing demand for timber construction has created a skills gap in the construction industry. There is a need for more skilled carpenters, joiners, and engineers who are familiar with timber construction techniques and materials. Investing in training and education programs is essential to develop a workforce capable of designing, building, and maintaining timber structures effectively.

• Opportunities for Innovation: The timber industry is constantly evolving, with new technologies and innovations emerging that further enhance the sustainability and performance of timber construction. These include the development of new engineered timber products, advanced wood preservation techniques, and innovative construction methods such as modular construction and prefabrication. Embracing these innovations can unlock new possibilities for timber construction and contribute to achieving higher levels of sustainability and BREEAM certification.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

4. Case Studies: Timber’s Impact on BREEAM Performance

Several case studies demonstrate how strategic timber use can significantly contribute to BREEAM performance. The following are illustrative examples:

• Example 1: The Cube, London: This nine-story cross-laminated timber (CLT) residential building achieved a BREEAM ‘Excellent’ rating. The use of CLT significantly reduced the building’s embodied carbon and construction waste, contributing to high scores in the Materials and Waste categories. The building also features high levels of insulation and airtightness, reducing energy consumption and contributing to credits in the Energy category.

• Example 2: Goldsmith Street, Norwich: This social housing project, constructed using a Passivhaus design and timber frame construction, achieved a BREEAM ‘Excellent’ rating. The timber frame provided excellent thermal performance, minimizing energy demand for heating and cooling. The use of responsibly sourced timber also contributed to a high score in the Materials category. The project demonstrates the potential of timber construction to deliver high-performance, sustainable, and affordable housing.

• Example 3: The Macallan Distillery, Scotland: While not a typical residential or commercial building, this project demonstrates the aesthetic and structural possibilities of timber. The complex, undulating roof structure is constructed from glulam beams, showcasing the versatility of engineered timber. The use of timber, sourced from sustainably managed forests, contributed to the project’s overall sustainability credentials.

These case studies highlight the diverse applications of timber in construction and its potential to contribute to high BREEAM ratings. They also demonstrate the importance of a holistic approach to design and construction, considering all aspects of sustainability from material selection to energy performance.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

5. Future Trends and Innovations

The future of timber construction looks promising, with several emerging trends and innovations poised to further enhance its sustainability credentials and BREEAM performance:

• Increased use of Engineered Timber Products: Engineered timber products like CLT and glulam are gaining popularity due to their high strength-to-weight ratio, dimensional stability, and fire resistance. These products enable the construction of taller and more complex timber structures, expanding the possibilities for timber construction.

• Modular Construction and Prefabrication: Modular construction and prefabrication techniques are becoming increasingly common in timber construction. These techniques allow for faster and more efficient construction, reducing waste and minimizing on-site disruption. They also offer greater control over quality and precision, resulting in higher-performance buildings.

• Digital Fabrication and Automation: Digital fabrication and automation technologies are transforming the timber industry. These technologies enable the precise cutting and shaping of timber components, reducing waste and improving accuracy. They also facilitate the creation of complex and innovative timber structures.

• Advanced Wood Preservation Techniques: New and improved wood preservation techniques are extending the lifespan of timber structures and reducing the need for maintenance. These techniques involve the use of environmentally friendly preservatives that protect timber from decay, insects, and fire.

• Focus on Embodied Carbon Reduction: As the construction industry becomes more aware of the impact of embodied carbon, there is increasing focus on reducing the carbon footprint of buildings. Timber, with its inherent carbon sequestration properties and low embodied energy, is well-positioned to play a key role in achieving these goals. Further research and development are needed to optimize timber harvesting and processing techniques to minimize their carbon footprint.

• Circular Economy Principles: The construction industry is increasingly embracing circular economy principles, which aim to minimize waste and maximize resource utilization. Timber, with its potential for reuse and recycling, aligns well with these principles. Designing buildings for disassembly and reuse, and utilizing recycled timber products, can further enhance the sustainability of timber construction.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

6. Conclusion

Timber stands as a powerful tool for achieving BREEAM certification, offering a multitude of sustainable attributes that align directly with BREEAM’s assessment criteria. From its renewability and carbon sequestration capabilities to its low embodied energy and contribution to occupant wellbeing, timber presents a compelling case for its increased utilization in the built environment. However, realizing timber’s full BREEAM potential requires a holistic approach that encompasses responsible sourcing, life cycle assessment, careful consideration of building regulations, and a commitment to continuous innovation. Addressing the challenges related to sustainable sourcing verification, fire safety, and skills gaps is crucial to unlocking the full potential of timber construction. As the construction industry increasingly prioritizes sustainability and embodied carbon reduction, timber is poised to play an even more significant role in shaping a more environmentally responsible and resilient built environment. Embracing the future trends and innovations in timber technology, such as engineered timber products, modular construction, and digital fabrication, will be essential to maximizing timber’s contribution to BREEAM performance and achieving ambitious sustainability goals.

Many thanks to our sponsor Focus 360 Energy who helped us prepare this research report.

References

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• Programme for the Endorsement of Forest Certification (PEFC). (n.d.). PEFC International. Retrieved from https://pefc.org/
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• World Green Building Council (WGBC). (2019). Bringing Embodied Carbon Upfront. London, UK.
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