Greg Cooper of B & K Structures discusses the positive impact which cross laminated timber has made within the built environment.
As construction makes up a total of 45 per cent of carbon emissions in the UK, sustainability is an important issue for the industry and one that should be addressed throughout every aspect of the build – from the sourcing of materials through to the long-term impact of the final structure.
As one of the most renewable mainstream construction materials, the increased use of engineered timber as the core structural component enhances the construction industry’s credentials not only from a sustainable perspective but equally from achieving optimum speed as well as performance.
Identifying and measuring carbon properties is now a fundamental part of any construction business. There are two ways of decreasing carbon dioxide in the atmosphere – by reducing emissions or by removing CO2 and storing it. Wood has the unique ability to do both.
We may commonly hear the term ‘carbon sequestration’, which is the process of capturing and long-term storage of atmospheric CO2. Solid wood products like cross laminated timber (CLT) are natural, renewable and are far less energy intensive to produce and apply. Compared to other building materials such as concrete or steel, the environmental credentials of CLT are far superior. Not only is it a renewable material, it involves very little waste during production and is extremely carbon efficient to transport. Moreover, for the production of each m3 of CLT, 676 kg of CO2 will still be stored after the manufacturing process.
To help monitor and reduce environmental damage in construction, a Carbon Calculator that gives carbon estimates to help assess the best ecological solution can be used. Material resolutions and transport factors are entered into the system and the calculator then produces carbon estimates to act as a guideline for different project scenarios. This enables professionals to gather early information about the ecological impact of their future development.
Companies leading the way in sustainable construction apply best practice principles throughout all aspects of their processes, from raw material procurement through to manufacturing and offsite processes as well as onsite assembly.
The Chain of Custody Certification for both PEFC and FSC outlines requirements for the ability to track certified material from the forest to the final product. This ensures that both the wood contained in the actual product and wood used throughout the production line originates from certified forests.
For the wood-processing industry, Full Chain of Custody Certification can improve efficiency and production systems by enhancing traceability and accounting. This means that all legal requirements are met, forest cultivation of sourced timber is managed well and forestry workers are treated fairly.
CLT as an off-site solution
Traditional building processes are noted to be highly wasteful in terms of materials and figures indicated that around 32 per cent of landfill waste comes from the construction and demolition of buildings.
However, cross laminated timber as an off-site solution can dramatically improve these statistics, producing significantly lower amounts of wastage, due to the factory controlled methods of construction. Recycling is far easier to implement in a factory environment, therefore cutting materials to size before delivery to site significantly reduces on-site waste and the associated expense of disposal.
As a rapid, robust and reliable off-site manufactured solution cross-laminated timber delivers many benefits during the construction process and beyond. From reducing loading on foundations through to impressive thermal, acoustic and airtightness performance – CLT construction has the capability to enhance projects across all sectors.
Reducing the loading on foundations is particularly important for inner city construction where the underground infrastructure results in loading restrictions. Using CLT as a lighter weight structural solution can increase, for example, the amount of storeys in a residential build – offering a better return on investment.
Manufactured to exceptional levels of accuracy in factory controlled conditions ensures minimal defects and improves construction and project delivery time, reducing costs and maximising efﬁciency on all levels, providing cost and programme certainty.
However the benefits do not end after the construction phase. Due to the enhanced performance values and robust nature of cross laminated timber, the on-going life-cycle costs of the building is vastly reduced through fewer maintenance requirements and lower energy consumption.
Finally, and most importantly, the design of a building can be critical to the well-being of its occupants.
Much has been written about the impact construction can have on the environment but very little on the effect a building can have on its occupants. The influence construction materials can have on the comfort and well-being of end users is an area where more research is required, however evidence is now emerging about the role cross laminated timber can play in enhancing internal environments.
Engineered timber, as a core structural solution, is gaining traction across the industry demonstrating that a wood first policy not only ‘stacks up’ from a construction cost and performance perspective but also in creating better buildings for people to live, work and relax.
Greg Cooper is pre-construction manager for B&K Structures.