very project is unique, and the client’s brief influences each design decision. Defining key drivers is, therefore, crucial in establishing the desired project outcomes. If the client intends to occupy the building for years to come, the brief may vary from that of a developer client with a remit to achieve a quick and efficient sale or, in the case of retail projects, to start trading and generating revenue as soon as practically possible. Structural timber systems can ‘tick’ many of the build and performance boxes.
With impressive environmental credentials, along with cost and time efficiencies, factory-manufactured structural timber systems with increased levels of prefabrication – offer greater control over quality, productivity and predictability. Integrated construction systems such as closed panel timber frame, structural insulated panels (SIPs) and volumetric modular options are now driving innovation in the timber industry – offering more choice than ever before. With standards for efficiency constantly ramping up, the construction industry has faced a real challenge in creating buildings that achieve the actual energy performance that is specified in the design brief. The accuracy and control involved in using timber-based off-site technology overcome this issue.
By investing in a robust, airtight building, operators and occupiers will see the long-term benefits that come from reduced maintenance and running costs – vital for public buildings such as schools and hospitals. Residential, retail and commercial developers have their own prerequisites with an emphasis on speed of construction – off-site-manufactured structural timber systems offer a faster return on investment for developers by delivering a quick and efficient build process.
The envelope needs to work for the owners and occupiers to ensure it is energy-efficient, low maintenance and provides a comfortable environment when the building is in use. There are many factors involved in achieving this and not just those that are visible. Considerations such as thermal performance, acoustic resistance, acoustic absorption and airtightness are all important factors when considering the build. Timber is uniquely placed to deliver on all requirements, not only for its sustainable credentials and aesthetic appeal but also its structural strength and adaptability.
For cities with complex underground infrastructures, such as London, there is an important financial equation – lighter equals taller. Lighter weight, structurally strong timber systems such as cross-laminated timber, reduce the impact on foundations so permitting additional storeys would be achievable using traditional materials such as masonry, concrete and steel.
Crucial to lean and advanced manufacturing is Design for Manufacture & Assembly (DfMA) protocols and Building Information Modelling (BIM). DfMA enables optimal configuration of off-site solutions on site by engaging with multi-discipline and multi-tier suppliers – ideally from the beginning of the design development process. This approach requires a change of mindset and a shift away from ‘traditional construction thinking’ to the adoption of assembly principles.
DfMA is used as the foundation for concurrent engineering processes, to simplify and fully optimise the structure in terms of budget, sustainability and performance – reducing manufacturing and assembly costs, with quantifiable improvements.
With recent industry reports underpinned by the recommendation made in the Building for Change Report by the House of Lords Science and Technology Select Committee – off-site construction has been gaining ground as a build method that offers numerous benefits. A reduction in construction time is one of the most notable, as buildings rapidly manufactured off site are less weather dependent. This, together with an improvement in quality through enhanced production processes in factory-controlled conditions, offers more predictable build programmes.
And finally, the most important benefit to any construction team – off-site manufacture for on-site assembly – improves health and safety and reduces working at height.
The use of structural insulated panel systems, timber frame, glulam and cross-laminated timber in optimised hybrid systems has been well-documented. Recent advances in pre-fabricated timber cassettes have led to pioneering large-format roof and wall elements that deliver precise dimensions and custom-made performance values.
Due to the wide range of possible applications, timber cassettes are used both in high-profile projects – which demand enhanced properties over and above standard Building Regulations in such areas as fire and noise protection – together with commercial applications requiring fast and cost-efficient construction. Detailed research and development into such systems positively contribute to building physics, ensuring actual on-site performance meets design expectations.
Achieving best value
Value engineering in construction has enormous benefits to both developers and clients alike. The multi-step process is an integral part of the design and development stage and is aimed at increasing value. The time invested in value engineering produces results and can be a cost-saving measure; however, it is becoming a respected project management technique that addresses all aspects of the building lifecycle, from the initial construction through to the sustainability of sourced materials and utility efficiencies of the final project.
Measuring value is complex and specific to each project and client brief. Using DfMA protocols and off-site techniques to fully optimise the structure in terms of budget, sustainability and performance are essential to all construction projects.
Investment in a robust, airtight building will reap benefits in the long-term from reduced maintenance and running costs – vital for public buildings such as schools and hospitals. Housing developers, retailers and commercial end-users have a different set of priorities with speed of construction rating as one of the highest. Optimised hybrid timber structures offer a rapid return on investment for developers, together with delivering a quick and efficient build process for the retail and commercial sector.