Hybrid timber systems – the optimum structural solution

There are many aspects to consider when designing a building – from the structural system and performance to the aesthetics and sustainability. Clearly the build cost plays a crucial part in the decision-making process – but does the lowest cost option really offer the best value?

Board Member of the Structural Timber Association and Managing Director of B & K Structures, Andrew Goodwin, offers his perspective on how to select the optimum building solution to meet the budget and specific needs of the client. There are many routes to take along the design and construction journey – selecting the core structural solution is one of the most important decisions. Every project is unique; 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 developers with a remit to achieve a quick and efficient sale or, in the case of supermarkets, start trading and generating revenue as soon as practically possible. For example, speed, safety and sustainability were the main influencers in the specification decisions for our recent project for Sky.

Hybrid structural timber systems, in my view, can ‘tick’ many of the build and performance boxes. Through the use of optimised hybrid timber solutions, contractors can transform traditional projects into more cost-effective, energy-efficient developments that ultimately have a positive impact on the environment and their profit margins.

By investing upfront 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, retailers and commercial developers have their own prerequisites with an emphasis on speed of construction. Optimised hybrid timber structures offer a faster return on investment for developers, by delivering quick and efficient build processes for the retail and commercial sector, buildings become operational in the optimum time.

For cities such as London, with complex underground infrastructures, there is an important financial equation – lighter equals taller. Lighter weight timber systems, reduce the impact on foundations so permitting additional storeys than would be achievable using traditional materials such as masonry, concrete and steel. This enables construction of up to 10 storeys, with experts claiming that a whopping 33 storeys may be achievable if innovations in timber technology continue on this upward trajectory. Timber could play a massive role in tackling issues such as the current UK housing crisis by providing high volumes of quality, energy-efficient homes at a rapid rate.

By taking a holistic approach to building design and construction, contractors can transform traditional projects into more cost-effective, energy-efficient developments that improve the bottom line. This presents a major opportunity and one that should not to be missed. All too often each stage of the build is considered in isolation – collaboration, communication and competent planning across design and development teams from the outset transforms project outcomes.

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 – not only those that are visible. Considerations such as thermal performance, acoustic resistance, acoustic absorption, airtightness and fire performance 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.

Design for Manufacturer and Assembly (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.

Off-site construction has been gaining ground as an alternative build method that offers numerous benefits. A reduction in construction time being one of the most notable – as buildings rapidly manufactured off site are less weather dependant. 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 enhances health and safety and reduces working at height. We were proud to recently announce that we were awarded the Royal Society for the Prevention of Accidents (RoSPA) President’s Gold Award for the 15th successive year and subsequently the RoSPA Order of Distinction.

The use of structural insulated panel systems, timber frame, glulam and cross-laminated timber in optimised hybrid systems has been well-documented, however, recent advancements in prefabricated timber cassettes has 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 in both high-profile projects, which demand enhanced properties over the 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 contributes to building physics – ensuring actual on-site performance meets design expectations.

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 stages and is aimed at increasing value. The time invested in value engineering produces results. Clients who define specific criteria for measuring value in the initial planning phase, experience increased satisfaction with the finished product and a reduction in overall project cost.

Value engineering 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 a complex and individual equation – 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 – in my opinion, is essential to all construction projects.

Initial upfront 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 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 – getting buildings on stream and operational in the optimum time.

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