31.08.2020 : Andre Kirstein

Thinking differently about timber

Andre Kirstein is a Senior Technical Director – Structural Engineering and leader of our timber business. He reflects on where his passion for timber came from, and the role he can play in New Zealand’s buildings future.

I can recall a hot lazy summer evening as a very young boy, biding my time away trying to hit nails into a plank of wood with one blow. My dad, upon witnessing this youthful bravado, asked me what life skills I would gain from this activity before suggesting I should do something more productive.

Years later I realised I should have remained focused and kept practicing as I managed to get so many blisters when building fences and decks, with the hammer coming to an abrupt stop against my fingers far too many times. Little did dad know about what was right for me at that time. Despite the pain and embarrassment at work on a Monday after a painful Saturday having just built the next section of the deck, I still have a passion for timber and its use in construction.
 

A durable material of choice

There are countless articles, papers and books written about timber and the benefits it brings to a building and society. Topics such as CO2 emissions, wellbeing, sustainability, environmental benefits etc. abound in their use for marketing mass timber in construction. This has brought the use of the material to the forefront of designers and clients minds. While sceptics use words like "fire spread, rot, noise, vibration, cost" etc. to discourage the use of timber, structural engineers have the skills and experience to address these matters - resolving or mitigating risks around fire and durability, while also considering the environmental and sustainability aspects of the building; to create a building that is not only safe to occupy but also fantastic to look at.

However, reading articles on designers or developers chasing the title for the tallest building possible with wood, or engineers boldly claiming to have developed the most complex lateral resisting system known to mankind, or those pushing timber as a material substitute with benefits, I often wonder if they’re doing the material real justice.

Some of the most beautiful timber buildings are low to mid-rise. Look at the Government Building in Wellington, New Zealand, that was built in the late 1870s for example. It was one of the world's largest wooden buildings for more than a century and is still admired today. The Horyu Temple in Japan is reportedly one of the world's oldest surviving wood structures and a more modern building, the Wood Innovation Centre in British Columbia, Canada has claimed accolades for its design.

“My belief is low to mid-rise buildings is where timber can play its part as being the material of choice.” – Andre Kirstein

Timber as the foundation of good structural design

In New Zealand, most of the building stock is low to mid-rise and therefore, you’d expect to see a greater uptake for timber. But you might find cost, floor to floor heights and vibration (to name but a few words), are challenged when timber options for designs are evaluated. And sometimes these can be viewed negatively if timber has been approached as an alternative to steel or concrete. Timber is not steel; it is not concrete - it’s a material that is different and it should be used in this spirit. Yes, it will require changes to what many are used to in terms of grid spacing or floor to floor heights, but let that challenge ideas.

Australia has embraced timber as a structural material of choice and acknowledged its benefits in the design of their buildings. Yet I feel New Zealand, a land where we pride ourselves on the beauty of our landscape and where forestry is highlighted, is behind in its uptake of structural timber in buildings. The “buzz” these days is for Mass Timber Construction where Cross Laminated Timber (CLT) is preferred. And what I observe, is New Zealand trying to follow the rest; pushing CLT developments and copying work overseas to catch-up. It appears this approach is resulting in box designs and mass production of residential developments. Why not embrace creativity in the design of medium-rise buildings by using a combination of all materials, maximising the benefits of each?
 

Staircase in Beatrice Tinsley Building, University of Canterbury showing prominent use of timber


The result is open, warm and welcoming entrance spaces, creative and unique layouts, inviting yet simple in build techniques. Not only are these designs attractive, they are also cost effective and may well be what people want to keep for years to come. Approach concrete, steel and timber in designs for the unique strengths they bring - try not to substitute each with the other. A concrete core building that is simple, strong enough to support high loads, with timber beams, columns and floors dispersed with long span steel beams may well be the best-balanced option for a design that allows each material to be maximised for its benefits and visual appeal.

At the end of the day a building, its owner or developer and the design team will be remembered by the community for a building that has a beauty about it, is inviting and unique, that is of value and ultimately one that they want to keep. That is not a timber building, it is just good design, but it uses timber.
 

A natural advantage for building New Zealand’s future

One of the biggest factors stifling creativity is often time and money. But one of the best ways to get around this, is to focus on working with people who are passionate about the project and invested in finding the best outcome including design aesthetics, buildability, use, future flexibility, durability and uniqueness. Appointing the entire team from the start enables everyone to come together as one to brainstorm and capture the best of all disciplines. Some of the most successful projects I have worked on are when we collaborate with our clients from the beginning – allowing the best solution to be developed together.

Let’s get ahead of the world by investing in smart, innovative, sustainable and carbon neutral (or carbon negative) buildings by using timber the way it is meant to be used; in combination with other materials, not as a substitute.

I’ll leave you with a final thought: the Canadian Government has heavily invested in the promotion of timber, thereby lifting and generating a huge industry. As a result, Canada is now recognised for being at the forefront of modern timber buildings. In France, the local government in Paris has pledged a greater use of natural materials, requiring all new public buildings to be 50% wood. Just imagine what can be achieved in New Zealand by bringing our beautiful countryside into a building.

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You might also like to listen to our podcast Getting to Carbon Positive: Episode 6 - Built environment. In this episode, Andre shares his views on the importance of rethinking the objectives of buildings and the value of making decisions around what materials to use in the early stages of a project. Such as timber, which has massive benefits in terms of carbon reduction and has changed the landscape of embodied carbon for buildings.

About the Author

Andre Kirstein

Senior Technical Director - Structural Engineering

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