CLT offers a range of benefits from structural performance to its aesthetic appearance. It’s well established for buildings between three and six stories and, internationally, up to 18+ stories.

We’re used to seeing steel and concrete construction but there’s an increasing trend towards engineered timber.

From the proposed Baobab project in Paris to existing buildings such as the Metropol Parasol Project in Seville or Forté Apartments in Melbourne, Australia, wood is a hot material.

When used for  high rises, it offers a legitimate alternative to concrete and can result in decreased construction time – as outlined in this article.

At present in New Zealand there is still an industry preference for more traditional materials, which means there is only a limited supply. However, we should absolutely persevere with it as the ecological benefits outweigh those of concrete and steel.

Using CLT, as well as LVL (Laminated Veneer Lumber) and Glulam is an area WSP has specialist expertise in. In particular, LVT has excellent safety benefits and can reduce the risk of building damage from seismic activity. Its use was key in our design of the Trimble Navigation Office in Christchurch which, at the time, was the largest pre-stressed laminated timber building ever constructed here.


Does wood cut it? The pros and cons of CLT structures*

In CLT’s favour…

+  Lighter structures save on foundations
+  Quick and easy to handle on site
+  Suitable for extending existing buildings within minimal modification
+  Smaller carbon footprint than steel or concrete
+  Sequesters carbon
+  Performs well in earthquakes
+  Structural performance is increasingly predictable
+  Locally available in many world regions
+  A popular “eco-aesthetic”
+  Easily prefabricated and well-suited to modular construction

… And against

–  It may be necessary to add mass to help with thermal performance
–  … and acoustic performance
–  Requires a reliable and sustainable source
–  rare outside Europe and North America
–  Not as carbon-friendly as might first appear
–  Yet to be proven above 18 storeys
–  The structure must be kept dry to prevent rot
–  Clients are sceptical of performance in fire
* This was originally published by The Possible.



Peter O’Leary, WSP Head of Structures, has considerable expertise in commercial, industrial, leisure and residential projects, both locally and globally. He is WSP New Zealand expert for offsite, which sees him working across to industry to help deliver offsite in the most efficient way.

The views expressed are the opinions of subject matter experts and do not necessarily reflect those of WSP.

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